My take on Kentucky Ballistics' Accident

Investigating gun related crimes and accidents is my core business, and my main area of experitse. Since I've already seen some ridiculous theories surfacing online, I decided to share my view on the topic, hoping to do some good.
I'm very happy Scott made it, and I'm sorry for all the parties involved in the accident and its consequences.
you can find Kentucky Ballistics video here: • My 50 Cal Exploded

[@ObiektTestowy]

Scott is a living proof that eye safety should always be your top priority at shooting range.

[@dan725]

YES. I already showed many of my friends the importance of eye protection from just showing the slo-mo of that video alone. I’m glad Scott is safe, and I wish it didn’t happen; but the fact that this event was recorded WILL save people’s eyes and even lives in the future for sure.

[@cafenightster4548]

Even when I tested my baby Ar's I wear a motorcycle helmet, body armor and gloves. I think he got too comfortable while testing unknown ammo, especially high pressure ammo in a .50bmg.

[@cafenightster4548]

Even when I tested my baby Ar's I wear a motorcycle helmet, body armor and gloves. I think he got too comfortable while testing unknown ammo, especially high pressure ammo in a .50bmg.

[@jadoncampbell2740]

@Adam 3m safety glasses are fine they are pretty strong

[@axelpatrickb.pingol3228]

That and having someone with you that has good trauma training...

[@markserbu]

Excellent analysis! You picked up on some very esoteric details....we should talk.

[@ringsystemmusic]

Oh hi Mark.

[@thelastcrusader8140]

A wild mark has appeared.

[@nobletaco2188]

No way

[@DiviAugusti]

@@ringsystemmusic I deed nahhht.

[@timothy2935]

Hi mark 🙌 hope youre good

[@WvlfDarkfire]

I love how the youtube firearm community can take a bad accident and learn from it.

[@opie7afe]

Or they spread horse manuer while lacking the qualifications to make those kind of assumptions

[@suprememasteroftheuniverse]

They didn't learn anything. They made up excuses. That's a supreme shame.

[@suprememasteroftheuniverse]

You'll end up losing the last gun rights and that's it.

[@angrydingus5256]

Agreed, and it was super wholesome to scroll through the comments on Scott's page and see support from literally all of KZbin's firearms channels. Great little (huge) community

[@ct7567CaptRex]

@@suprememasteroftheuniverse you got a licence for that nonsense?

[@GenScinmore]

Excellent explanation, very in depth. You really deserve more subscribers. I'd like to add that the ears that ironically almost killed him, also likely saved his life. If those ears weren't there then the unimpeded cap probably would have taken half his head off 😬

[@ExoDead9]

It’s farmer fudd

[@brian13m3g4]

IF they weren't there then this gun would be really dangerous to use because those let you know if the cap is on all the way

[@rronmar]

Or a stronger ear structure behind the breech cap, and a weaker hinge mechanism forward, so an overpressure failure such as this would tend to throw the barrel forward and less chance of throwing anything to the rear toward the shooter...

[@GenScinmore]

@@rronmar totally agree

[@UncleDon226]

I think the safety glasses did more than the lugs behind the breech did. Those safety glasses absorbed a significant amount of the impact. Wear your eye-pro kids!

[@mattpeacock5208]

It's a bad day when ammo that costs THAT MUCH breaks your gun and almost kills you. I always say, don't buy cheap ammo, but he didn't even do that!!!!

[@marcusborderlands6177]

i mean, my rule has always been dont buy super cheap ammo or super old ammo. both can do disastrous things

[@not_a_samsquamsh6777]

No, but he did buy very old ammunition

[@waterdotzable]

He was also buying unusual rare ammo

[@justindunlap1235]

@@waterdotzable with an unknown history.

[@mattpeacock5208]

Yeah, rare and old, maybe I'll avoid those. Nice safety tip.

[@brickct123]

Serbu is already getting his hands on the remains of the rifle, he posted a video earlier today.

[@spetursson3640]

While they wait they can start reproducing this scenario in a safe test lab using an identical rifle and bad ammunition.

[@timothy2935]

@@spetursson3640 that would be beautiful

[@laneshirley3706]

What is he gonna do with it tho ? Is he planning on increasing the strength of the lock cap or something

[@darkman30200]

@@laneshirley3706 At the moment no one knows, mainly its going to be inspected to look over the results of what happened, but most likely it'll be used as a test bed to come up with some designs to help prevent more issues like what happened to Scott from coming up again. Given the ideas BB mentioned in his video just now, he'll probably modify the design to include more fail safes.

[@patrickr2686]

I bet there's a federal investigation looking into this (ATF)

[@joystickricksherrell774]

Wow! A person who can humbly suggest improvements without sounding like a know it all...Cheers!

[@DrewWestPress]

As soon as I saw this gun I was like “yeah, that’s asking for a serious injury.

[@VikingNorway-pb5tm829]

@@DrewWestPress Same here ;)

[@2oceans1]

This is a genius that is totally comfortable in his expertise. A humble man. Refreshing to see this man at “work”

[@archangel20031]

The SLAP round that detonated was overpressure, but the SLAP round before that also showed signs of overpressure as well with the round deviating from where it was aimed and the huge fireball it produced.

[@kriztov265]

It looked like that round was totally wrong. Maybe as a result part of the projectile was lodged or extruded into the lands causing even more drag and causing the rise of pressure to become catastrophic. The flyer round may have been the setup. Im sure Scott will be even more aware when something doesnt feel right to stop and reassess. The drag caused by sealed heavily crimped surplus ammo can be a factor in some case issues and can be overlooked at times.

[@peteengard9966]

Someone needs to remove the rounds from the remaining cartridges and measure the powder charge. The muzzle flash of the second round was tremendous compared to the first round.

[@zachjunge6413]

One video explained how the slap rounds were not to be shot out of certain muzzle breaks because they cause buildup from the sabot which would explain the accuracy problem and increased muzzle flash and pressure with each shot

[@alberto5770]

@@peteengard9966 in competition shooting or hunting you end developing your "token" rounds toying with coating the lead to reduce barrel debris, measing loads to be in the higest level and accuracy with the less recoil... I am afraid those 100$ rounds mass produced decades ago MIGHT lack suck detail and not every recreational shooter will be able to study them.

[@Peasmouldia]

Sabot rounds can easily foul the muzzle brake. That's what we saw with the previous flyers.

[@Taylor-mq6fk]

I’m so glad he’s ok

[@uiopuiop3472]

I hope too

[@ScottKenny1978]

@@uiopuiop3472 Scott from KB is healing pretty well, he's out of the hospital (was out when he posted that "my .50 BMG blew up!" video). Dude needs to give his guardian angels some time off after that!

[@torquetheprisoner]

he is a very lucky guy good thing that he was not filming alone to

[@Dodo-ze5ep]

It's the topic of the week literally on every gun channel

[@darkman30200]

I mean it IS a pretty big deal when a .50 cal rifle explodes and almost kills a beloved member of the community.

[@killertruth186]

@@darkman30200 It is, when a big gun turned into an instant frag grenade.

[@ytucharliesierra]

It's gone viral because of its uniqueness: never before has such an event been documented so thoroughly.

[@GunGuy258]

It's because a 50 cal round malfunction is like a pipe bomb going off in your face. It's a pretty big deal. Glad he survived.

[@aspjake123]

What else would you expect

[@OkieDokieSmokie]

The wholesomeness of this youtube community is amazing.

[@DanGoodShotHD]

What?! But haven't you heard? The gun community is a bunch of racist gun crazed nazis out for blood. Seriously though for the overwhelming majority, despite what certain political groups would want you to believe, it is a very wholesome community that I'm proud to be a member of.

[@alanwatts8239]

No thanks to taofledermaus for that stupid rant-reaction video.

[@OkieDokieSmokie]

@@alanwatts8239 I think people are just overreacting about that.

[@angrydingus5256]

@@alanwatts8239 Seriously though, that shit was mad distasteful. Made me unsub so fast I almost broke my thumb.

[@alanwatts8239]

@@angrydingus5256 Same here, it could have been avoided but he did it anyways just a day after scott's video, he isn't worried about anyone more than worried about his money.

[@woodbury4567]

I have my own theory about what happened there, the SLAPs that Scott was using were most likely counterfeit (as evidenced by the lack of crimping at the top of the case unlike on a genuine SLAP) and the sabot was probably made from poor quality brittle plastic. If you look at the entire sequence of events he fired a SLAP round that had an excessive muzzle flash and extremely poor accuracy, then he fired a red/silver tip armor piercing incendiary tracer, then he fired another SLAP and that was the one that exploded the gun. If you look at the military specifications for SLAP rounds it says in the notes on page 11 that excessive muzzle flash can indicate the sabot has broken apart before leaving the barrel and the way to check if this is the case is to inspect the bore for damage. I suspect that the first SLAP broke apart causing the tungsten penetrator to bounce around as it went down the barrel and damage the bore. The damage to the bore may have been light enough to allow the APIT to fire seemingly ok but significant enough that when he fired the second SLAP the damage caused the sabot to violently disintegrate and the tungsten penetrator dug into the bore and became wedged causing an obstruction (possibly only a temporary one) and pressure spike. The rounds may not have been overpressured at all.

[@zyobr]

Same thoughts. Also, nobody seems to talk about the muzzle brake, so I assume it was made suitable to fire saboted rounds. Can't wait to see Mark's analysis

[@jetsonIFY]

excellent.

[@cav4353]

sounds plausible, well said.

[@ScottKenny1978]

@@zyobr correct, sabots don't like most muzzle brakes. The guys at Going Ballistic have a really cool machinist that made a liner for their .50 rifle, to hold the sabot together until the whole mess leaves the brake.

[@matteoorlandi856]

I was thinking the same. Those SLAPs ammo have incredibile prices, and you Need a cheap Lee 50 Press to reload 50bmg. Someone can made good money selling fake ones...

[@rickoshea8138]

First four threads in engagement taking most of load is true when thread material stress falls within elastic range. When stress in first four threads exceeds yield point, then having more threads starts to help. So, more threads are useless, except when you really need them...

[@Artcore103]

My thoughts exactly.

[@Rosy_87]

I agree with you Rick. Had there been twice the thread engagement it would have been unnecessary and redundant until the first 4 threads gave way then there would have been 4 more to take the load. Redundancy in this case would be worth the cost. If the cap was able to be removed the failure of the first threads would have likely been visible. I'm definitely not an expert and wont pretend to be one, it has been interesting to hear all opinions expert and amateur.

[@Jarmoust]

I was looking for this comment. I not sure what he thought when saying that. Its not like the remaining threads will magically brake whit the first 4 carrying all the load. I think that when someone is designing these kind of important parts, they should calculate the maximum load that the part is going to be experiencing and make it proprietary stronger than that. This part looks like it was designed whit only the ease of use in mind.

[@shubbagin49]

From an old Scottish squaddie, seen a few accidents, my oppo had a GPMG explode on him, 2nd Para, he wore glasses? Anyway, he survived, always had a small scratch on his glasses lens, he said it was because he held his eye so close to the sight, he certainly kept heads down. Lucky you are Sir. British Army 1976- 1983

[@colderwar]

A good friend of mine was a REME Armourer and he disliked two service weapons in particular - the L42A1 because it was a pig to do the bedding on according to the regs - so it shot accurately - and the Gimpy, which he said was a great weapon apart from the rivets which held the receiver together becoming loose after time.

[@preacherbiggin]

Seeing the gun community come together in times like this, shows how much we care. It is a testimony to the type of people we truly are. Not the "hit pieces" the media always try to label us negatively in. Great job fellas! Proud of our community and the love and support we have for each other!

[@Floortile83]

Hello. I am representing the government. Please join us in banning guns to protect people like scott from himself.

[@ShadowSniper2307]

@@Floortile83 bot

[@josiahwyncott7519]

I thought your shirt was a stylized depiction of a butterfly until I realized it is a side-by-side shotgun.

[@smilz0]

Dude, i was seeing an owl's face until i read your comment. The shotgun makes definitely more sense lol

[@SgtRudySmithbRet]

Lol it's a biden pro gun shirt.

[@eightbittemplar7394]

@@smilz0 Seconding the owl, although I can see the butterfly now.

[@kbckj]

It's what you want it to be, it's a great design.

[@F1god04]

@@smilz0 I think it’s a shotgun face that is made to look like an owl. An owl is a symbol of wisdom and knowledge and I think OP wants to combine firearms with his own knowledge and clear wisdom. He wins there in my book! He knows what he’s talking about and is clear and concise. I like!

[@JohnDoe-vf2yo]

Good to see that you took a scientific approach to what happened with Scott and didn't criticize him like Taofledermaus did in his video because of another "adpocolypse" or scared of his channel being shut down.

[@ineedmymodfixed]

I've been owing taoflafermaus for a long time but that video he posted really missed the mark. He definitely shouldn't have put that out there.

[@jic1]

I think he was more predicting some of the likely negative consequences of Scott's video than truly criticizing him; but yes, I don't think it was the best response.

[@MAGAMAN]

This is not a scientific approach. He said the screw on cap was not the fault, when it was literally the failure point. He said the threads were too strong to fail when the threads were literally sheared off. While the initial cause of the problem was the round, not the gun itself, the way the gun failed is 100% due to poor gun design. I mean, if you are using the 50000 genders "science" approach, then maybe I guess...

[@conductorcammon]

@@MAGAMAN don't think you understand the difference between HOW it failed and WHY it failed.

[@NTAD]

@john anon This guy didn't even watch all of Scott's video. He probably just skipped to the part where it blew up and suddenly fancied himself an expert.

[@Deploracle]

One thing that may have been missed. The damage to the threads could have been caused by successive overpressures that day that went unnoticed. The last hot cartridge may have been the last straw. Much damage can be done to heat treated steel without there being much visible to the naked eye as evidence. Probably a good idea to not exceed recommended pressures.

[@briancolstock5276]

I went back and watched were the previous shots were scattered from the point of aim and wondered if something wasn't already going wrong.

[@ronaldcadorette4353]

When I watched the original video of the accident, it occurred to me also, that the previous hot rounds could have caused metal fatigue which did not manifest itself until he fired the last round. Further, when you purchase a device such as a rope sling, it has a built in safety factor for safe operation that is one third of its breaking strength. This was obviously not the case with this rifle design.

[@theknowitall2280]

@@ronaldcadorette4353 -you are correct ! finally, someone here making sense

[@eliabrahamson7255]

This was an impressive analysis. You literally covered every angle and explained the topic perfectly. Your ideas for additions to the gun to make it failsafe are the only intelligent suggestions I've heard on this incident so far. Well done!

[@marzcapone9939]

Ian, from Forgotten Weapons, touched on how vent holes were used on one of the Arisaka rifles.

[@mojaveslayer5724]

I did some of my own research on the SLAP rounds after the release of Scott's video, I found countless reports of these SLAP rounds damaging the inner mechanics and barrels of rifles, and upon further inspection found out that these SLAP rounds were never meant to be fired out of rifle platforms, they were originally designed to be fired from the M2 browning and was the solution to light anti material for tank crews

[@dan725]

This is absolutely fascinating and putting lots of hearsay to the Serbu rifle design to rest. I’m so glad you put a full stop onto any possible faults that the rifle may have had with concise explanations. Thank for you that. It’s important that video must be spread about. I also feel like it may be a good idea that Serbu provide free modified caps to all owners with vent holes and added weight like you explained. I know it’s not the rifle’s fault, but given the scrutiny involved, people still may refrain from purchasing it just from a single freak accident when such a thing could happen to pretty much many rifles.

[@MAGAMAN]

The rifle was literally the failure point. You people are all on drugs. Anyone who would fire one of these files after this is an idiot, because you never know when you could get one of these rounds that almost Killed Scott, and you might not be lucky enough to have someone who knows exactly what to do in this situation next to you. I have seen lot of gun failure videos and none of them have failed in such a deadly manner.

[@deepfriedpotatoes9888]

@@MAGAMAN shooting modern .50 bmg is fine in the rifle, as long as you aren’t shooting sketchy SLAP rounds.

[@filadelfozuniga3411]

@@MAGAMAN Any gun could fail if you use the wrong amunition, or amunition in poor shape, that slap round probably meet both of those criterias. If you are gonna push that boundary get other rifle that you would trust more to explode safely, as silly as that may sound.

[@Hornet135]

@@MAGAMAN there’s dumb, and then there’s you.

[@LoremIpsum1970]

Good video, cant wait to see Mark's analysis. If you've seen Ian McCollum's comments on forgotten weapons he said same as you. Maybe not having the lugs isolated but continue to the back of the reciever so they cant break off as single pieces? Hell what do I know?! Interesting to see where this goes.

[@dan725]

I think current owners being provided a modified heavy cap with vents could be a solid solution.

[@Mike_Rogge]

I watched mark's video, he will apparently be doing some testing and trying to get his hands on the RN-50 in question.

[@hornmonk3zit]

My idea was to recess the chamber and have additional male threads on the inside of the breech cap that thread into the recession so you get two separate areas to lock the chamber closed. Other than that I had the same idea as Backyard Ballistics, vent holes and an external receiver to catch shrapnel.

[@LoremIpsum1970]

@@dan725 certainly sounds a lot better than making changes to the receiver. I’ve not studied rifles close enough but I do know the Lee Enfield had a vent hole in the breech in the event of cartridge failure. It’s easy after an event to see problems but how far you take ‘what ifs’ at design always has a certain limit. Anyway this is best left to the experts!

[@avlawns3037]

Ian knows history, but dick about engineering. Sorry, but true. His whole garands dangerous with commercial ammo videos proved that.

[@isellcatlitter]

i can't believe that rifle did not have a gas failure port on it, the Germans knew about catastrophic cartrige failures in the very early 1900's.

[@shaneebahera8566]

thats because the rn 50 started off as a homemade 50 cal

[@markbuitenwerf2000]

This would not heapon if the cartridge whas fired from the gun of whas disigned for the m2hb The m2hb could have been destroyed by that hot cartridge but the damage would be much less

[@shaneebahera8566]

@@markbuitenwerf2000 the problem is that there are no fail safes like found in any other gun, in most guns the fire arm would be wrecked but it won't send bits of it into your head, like serbus own BFG 50A

[@markbuitenwerf2000]

@@shaneebahera8566 Exactly if this heaponed with a m2 al the schrapnel would be contained in the gun itsself

[@strayblackcatsmeow]

He said that the recoil increased with each shot. My understanding was that the round was designed for a smooth bore machine gun tank barrel, if so the rifling in his rifle would strip off material on each shot and the build up in the barrel would increase back pressure on each subsequent shot until pressures exceeded critical. The fault would be shooting non compatible ammunition.

[@Lucifurion]

The RN-50 is designed to handle SLAP rounds with no issue. Scott's problem was that he had bad rounds & the one that blew up the gun was loaded way too hot.

[@benjaminpainter378]

I have an email drafted that I was going to suggest this to you hahah. Great job on being ahead of me!

[@layo42]

Hey Ben what's up

[@benjaminpainter378]

@@layo42 that's hilarious you found my comment

[@GVALNIER]

Man. IMHO those caps shold not be used in guns.

[@greyclouds6052]

Keep uploading. Your presentations and insights are unique.

[@andrewnewton9137]

I was expecting this to be another KZbin "Expert" but instead it was a really good detailed and concise summary. Well done

[@mooseman684]

In my Expert opinion as a Master Gunsmith over 40 years it was either a SEE explosion of the Powder in the round or a sabotaged Round from some foreign conflict as have shown up on the market in years past. No gun can withstand a SEE event that generates in excess of 100,000 PSI ( Tests in a New Zealand Lab showed a Pressure spike of almost 150,000 psi during a SEE test from a normal powder charge that was reduced and should have generated about 45,000 PSI in a cartridge) , as the steel isn't rated for that kind of pressure spike . Great Video !

[@sfranger50]

I can only support what has already been said. This is a concise analysis delivered in terms any layman can understand. My thanks to Backyard Ballistics; I have subscribed and will look forward to checking out more content. Finally, my sincere support to Scott and I hope he makes a full recovery.

[@michaelvstheworld3680]

More information: In a previous video from Kentucky Ballistics titled "50 Cal vs Atlas Stone", Scott somewhat stated he knew SLAP rounds could not be fired out of certain 50's. So Mark Serbu sent him machine gun, oversized chambered, heavy profile barrel. Again, just some more info.

[@Kickstandsup83]

it has more to do with the mussle break then the barrel. kzbin.info/www/bejne/l6PHqGNviJx6nKc

[@Sp00kq]

The heavy barrel was necessary yes, but as the other reply pointed out, the muzzle break was also a bigger problem. The bullet from a SLAPT cartridge is actually not a 50 caliber bullet, so it is set in a plastic sabot that is half an inch in diameter. Muzzle breaks don't like sabot and it can cause some big problems. It's why modern tanks that shoot sabot ammo don't have muzzle breaks.

[@michaelvstheworld3680]

@@Sp00kq the oversized chamber was also an issue with the high pressures. If you stand against a wall and I push, you wont move. Now, take a step forward and then I push you against the wall it is a different story.

[@IraChandler]

"brake"

[@alanwatts8239]

Now THIS is a good and respectful reaction video, you pointed out amazing points about the situation and stayed very professional throughout. Now, TAOFLEDERMAUS's reaction video was insanely disrespectful to Scott and his viewers, calling his subs "fan boys" and calling his video a "full-grebner" video. He says the video of his gun blowing up might become a meme, and he's the first one to make a meme out of it by calling it "full grebner". As if it wasn't bad enough already, he is clearly more worried about gun channels being censored or pulled out to recommended sections than worried about Scott. I unsubbed instantly.

[@harreeadorable15]

I will soon do the same. Thanks i wasn't aware he did that.

[@littlejohn-pi7kk]

That is so disrespectful. Guy barely survived and here they are worrying about their bank account.

[@lousbits]

I'm not sure if that's completely true. He was more worried about the KB film being used against him, out of context, to make him look dumb.

[@blshouse]

Way to totally misrepresent the video.

[@NotKidding52]

with viewers like you completely misunderstanding his video, I'm sure he'd thank you for unsubbing.

[@gerthddyn]

That was an incredibly careful and insightful examination of the accident and the recommendations at least sound relatively cheap and easy to implement. Thank you for describing it. I'd never seen your channel before.

[@Dsdcain]

Very good analysis TBH. Keep making great videos. Always great to see new ones.

[@546people]

What a great display of your day job. Concise and clear. Even I could comprehend your message.

[@BarqueCat2]

Thank you for this very clear explanation countering the wild theories and accusations. I appreciate you taking the time to address these.

[@EdgewiseChairman32]

Great video. First video of yours that I have ever seen and it did get me hooked. Great job. The information about the threads and their load bearing was new to me and really surprising. I thought for sure the threads would break before the bolt itself. Thanks for educating me!

[@abelgerli]

I agree with the ventilation in the cap. Even the very old Lee Enfield has a ventilation hole on the top of the locking mechanism to prevent to much pressure I case of a blockage or a to hot round.

[@MrBilld75]

After seeing your comment I figured the old Mk2's also have it, as they are basically modeled after a Lee Enfield, just with a shorter front stock. So I checked mine and indeed it does. Although, I didn't actually look at the locking mechanism, like you said as it is uncocked and has a lock on it right now and I can't be bothered checking it out thoroughly, lol. But it has a hole on the left side of the barrel/breach, right about where you would expect a vent to be.

[@abelgerli]

@@MrBilld75 You are right and I can only say it works when the primer gets fully pierced. I wondered what's that it blows to the right ? Then I looked at the shell and saw the primer with a whole . So I think it was intentional. But if this would be sufficient in this case may be. On he other side there is a whole lot of metal to shear of on the bolt of the old Lee Enfield 🤔 So would have may be a bit concerned with this mechanism.

[@MrBilld75]

@@abelgerli I love the bolts on those guns. The bolt on my Mk2 is like butter, but yeah, it's quite robust , the whole gun is really, they were well built and good all round guns in their day. That hold their own against modern rifles and even it's nemesis, the Mosin Nagant. And can even trump it in a few areas. One of the most enjoyable episodes of R. Lee Emery's military show, was when he pitted the Enfield against the Nagant and it was a pretty even contest overall. Yes, the Nagant was a great long range gun and the choice of Snipers, but the Enfield was no slouch and the Enfield was MUCH faster. It's been used in long range shooting contests to this day. King of "the mad minute" and the fastest bolt action in the world. It's some beautiful 1940's engineering unbeaten to this day. Matched, sure, there are some beautiful bolt actions out there, but none beat the Enfield or any of it's copies. It's actually the only rifle I own and was an inheritance item, but I truly learned an appreciation for it after owning it and using it. Only flaw they ever had was jamming and it was very easily avoided, by an old tip from the men who used them in war. Never load them with their full capacity of 10 rounds, that's what causes the jam. 8 rounds it never jams and then this is a very reliable and legendary gun. Our Canadian Rangers used them right up until a few years ago. The Afghani's pinned down an entire American platoon with them for a long time and it's incredible to think they could do such, with old 1940's rifles, vs. modern 1st world well outfitted military with all the latest tech, but they did. Lol. They have clearly got skills with these old rifles. They have pretty much limitless ammo for them, so they literally don't care and just fire them constantly at them. The American soldier telling the story said it's hard to believe, but where they were and where the Afghani's were (and he was in a spot very similar), they had them from higher ground and semi boxed in. So, what are gonna do? Stay put, nobody wants to argue with a lot of .303 British rounds, lol.

[@abelgerli]

@@MrBilld75 I can't agree more I own No I and 4 in .303 and the .22 lfb as well as the jungle carbine in both stock variants with metal in the front and without. It was more interested in the English and commonwealth rifles despite being German. May be the interest came because i am very history aware an I feel still in dept to Churchill. I have a problem with fascists and communism as well so that's may be the origin of it. I also visited Hiroshima and Nagasaki on separate visits to Japan and my opinion is that no world leader capable of nuclear strikes schould begin his office without visiting the memorial sites. The lessons of history are to far away now we have to prevent future mistakes especially when you get a moron in a office. Can't believe the US learn more about the democratic process from you in Canada 😉.

[@MrBilld75]

@@abelgerli Oh wow, that must have been interesting. I've only seen pictures and heard stories from survivors of Hiroshima and Nagasaki. So you have the .22 version as well huh? That's not one you see that often, we had a Canadian version of it too that was nicknamed the "Wildcat" and was a necked down .303 to a .22. A lot of guys who bought them surplus, wanted a dual purpose gun, high power, but capable of small game rounds too, so they necked down those .303's to a .22. Not a common find nowadays, but was a fairly popular thing once upon a time.

[@larryjohnson150]

I work as a gunsmith so just seeing those schematics you have framed in the background got my subscription!

[@hodge12009]

I love this analysis, it doesn't just go over what happened but also what could be done to make sure it doesn't happen again!

[@josch614]

I do very much like the fact, that you expressed your sympathy for Scott first and follow on with a focused topic. Even being a big fan of Ian I missed the first part in his vid & was totally puzzled about what Jeff was talking... I hope he was still under shock, as we probably all where.

[@josephhomen]

This is one of the best video’s I’ve seen on KZbin ever. Great job thanks 👍

[@franklinAll8735]

Do you think that Barret M82 or BM Ma-50 or similar design would handle such catastrophic failure much better for the user? It seems striking to me, that Rn 50 safeguards are totally unadequate and the design unsafe by allowing the cap to fly right towards shooter face. I beieve that in case of Barret M82 in case of such catastrophic failure, the lugs would be probably shreded but the recoil spring would do a good job of slowing the bolt just enough so that sturdy receiver would catch it and prevent any serious damage to the user.

[@spetursson3640]

Yes, I think so. What happened to Scott has reinforced my belief that the most important role of the ejection port is safety. In the same vein I advise all my left handed brothers and sisters to use firearms with ejection ports on the left side.

[@jacktheaviator4938]

The design is flawed in the fact that it has pressure bearing parts, which are moving, that are not contained inside a receiver, and it has no safe path for overpressure. The fact is, no major manufacturer in the world, people like H&K or even Taurus, would have NEVER let a weapon that even has to contain full power rifle cartridges on the market without a "plan b" for overpressure. Gun design isn't about building a gun that operates safely when things go right, it's about making sure the weapon stays safe even when everything goes wrong. They do things like failure overpressure tests. But when you buy an original design from someone like Serbu you don't get that failure testing. He can't afford, and doesn't have the facilities, to blow up 100 rifles to see how they fail.

[@avlawns3037]

@@jacktheaviator4938 where exactly is the anti kaboom cut on my hk91? I cannot seem to find it. I do have one blown into a pretzel that almost took my hand off when a locking recess failed.....

[@SP-ls8lw]

The whole reason the first thread carries so much of the load is because the metal behind reinforces the threads, meaning the segment is still stronger as a whole with a higher thread count. As the front threads begin to yield, the following threads will pick up the load. Oh, and ACME threads have a much higher shear strength. You know, square vs triangle geometry.

[@nooblangpoo]

Yours and Ian's explanation really gives more details on how gun/ammunition failures are studied upon. Great job!

[@silverbackhayabusa]

This video was recommended and I was sure I was going to hear some clown talking out of his rear. I was very pleasantly surprised with the analysis provided.

[@OnTheRiver66]

I hope someone tries to find out where that cartridge was loaded - there may be more out there.

[@ikillacommunistforfun320]

You know he knows exactly who he got it from. I'm pretty sure Scott had a talk with him.

[@emmachamberlain7587]

@@ikillacommunistforfun320 never trust old ammo or other peoples re loads !

[@ChoppersModelworks]

Keep in mind the volume of high pressure gas that will be vented when a .50 BMG breach fails. In my own brothers unfortunate case he just happened to raise his head before firing so the entire bolt minus its stripped locking lugs (interrupted threads in his case) just took off the top of his shoulder. It was the high pressure gas that vaporized his glass lenses into and through his right eye. It was also the high pressure gasses that blew open almost his entire right side of his face. For reference they did eventually find the damaged bolt about 50 years behind the firing location. So while i agree venting of the cap is a good idea i would be cautious of adding weight to the cap. Also just keep in mind maintaining consistent hardness and temper in traditional 60 degree threads can be problematic at times due to cool rates. Surprised they didn't use a buttress or even acme thread profile to give more mass and cross section to the thread.

[@onlyforviewsreturns1653]

Great video. I'm always amazed (and frequently surprised) when KZbin suggests a video that's both interesting and actually informative. I'd been taught about thread loading, but it hadn't been knowledge I'd needed for a really long time. I was looking at those thread and wondering. Now I know better (again.) Fascinating stuff, going to subscribe and go along for the rest of the ride.

[@sonnyburnett2417]

I hope that Serbu adds more safety features to the RN-50 (like the ones you suggested). We can't be sure that these would have kept Scott (or the next shooter that fires overpressure ammunition) 100% safe, but it's worth trying (and I think we can all see the RN-50 has a lot of room for improvement in this area either way).

[@imsimplyalan]

Mi fa veramente piacere che anche in Italia abbiamo persone così competenti su questo tipo di argomenti veramente bravo 🎉

[@tunderstorm2769]

io mi sono iscritto subito avendo notato il suo accento

[@imsimplyalan]

@@tunderstorm2769 stessa cosa

[@tunderstorm2769]

@@imsimplyalan che poi e pure bravo

[@neogator26]

As an aerospace engineering major I really liked this video. Most wouldn't have explained how the lower velocity of the object significantly reduces the KE since the KE is calculated by velocity squared. Great analysis.

[@neogator26]

I guess Scrappy retracted his comment about my education and my school when he realized he didn't know what he was typing after all. Don't worry Scrappy, I highly doubt you will ever qualify to fly on anything designed by engineers from my school. Your name won't likely be among those of Lovell, Duke and Cernen just to name a few. You can rest easy.

[@JamieStuff]

You forgot one other possibility - user error. DO NOT use a sabot round in a firearm with a muzzle brake (or suppressor) unless that muzzle brake is designed for sabot rounds. The design of the sabot is to detach itself from the projectile as soon as it leaves the barrel; much like the wad does in a shotgun. It starts to peel itself away inside the muzzle brake, and if it touches the side of the muzzle brake, it will deflect the shot. This (wandering point of impact) was happening in the shots leading up to the accident. The sabot can also leave a "skid mark" of plastic a few molecules thick, further constricting the exit. A little too much friction, a little too much deflection, a little too much time taken to leave the barrel, and you get a pressure spike that can result in what happened to Scott. The RN-50 has NO provision for an overpressure situation like that. Had he been shooting a Barrett that day, he may have destroyed the gun and got a few lacerations or burns, but likely nothing life threatening.

[@shanebisme]

Great suggestions on how to improve the rifle and make it more safe for the user.

[@chrishooge3442]

That was an amazingly detailed and yet brief explanation of what we know. Well Done. Ciao.

[@spacecatboy2962]

thanks for the insight, a few things jump out at me about what happened, one is that it is crazy how bad he was hurt in that they sawed his chest open as if he was getting a heart bypass, two he would have lost his eye if not for the safety glasses, or might have even been killed or gotten long lasting brain damage from the cap, three, its crazy that he was hurt this bad and a couple weeks later he is walking around and shooting a gun. One big irony is that his hand that was gripping the gun was not hurt, but his other hand was broke while resting it on the table.

[@Nobody-Nowhere-USA]

The manufacturer has a stellar reputation and in this very thread has demonstrated why that is so! This video is a great analysis of what probably went wrong and manufacturers reaction and willingness to listen to other’s opinions is the very reason he will continue to be successful in this market! I , for one, am impressed! So glad our friend survived his close call and is on the mend! He has a great attitude and I think he will be back to providing interesting content like he always has!

[@jameswitte5167]

I believe WW2 Japanese Arisakas have the vent hole you mentioned ...

[@bonogiamboni4830]

Yep, gun jesus (ian from forgotten weapons) also did a video on this accident and showed the arisaka with its vent hole as well as some other rifles with other failsafes.

[@Sman7290]

Look at a modern day Bergara rifle. They also have a gas vent hole to relieve pressure and direct gas in the event of a case failure.

[@David-hm9ic]

The Mauser M98 and its variants also had gas redirection.

[@jameswitte5167]

@@David-hm9ic Can't rememer if my GEW 88 had one or not ...

[@MrBilld75]

@@bonogiamboni4830 Lol, gun Jesus, hahaha. Yeah, awesome gun Jesus though, I like his channel. Such cool weapons and guests he covers.

[@alex_7547]

Thank you for your insights. Kentucky is very lucky to be alive.

[@MrBilld75]

Nice to see it addressed by a forensic crime scene investigator's point of view, that was very interesting! I don't think anyone can argue your excellent explanation of the physics and pressures and what happens when it invades the threads. Nobody has addressed such a thing that I've seen. Although I would disagree that mostly the first 4 threads counted "in this case". Because when they fail like they did, more thread engagement, would mean better chance of it not shearing off like it did (although it still might have, more kinetic energy would have been absorbed by it) and perhaps slowed it down. I still think it should be a bit beefier and a guard like you said and even better ears. But I don't blame the ears or gun or threads, it was that ammo absolutely and being fired out of that gun. You're not supposed to fire saboted rounds out of muzzle brakes, they are known to cause issues and that shot just before the disaster shot, proved it. That was a huge muzzle flash and a warning of what was to come. There's a reason sabots are fired from only non-muzzle brake guns, even in the military and even on tanks. It's a recipe for disaster with a brake, as witnessed there. There's a saying with pressure vessels, "don't mess with pressure vessels" lol, they are extremely dangerous and can put some other explosions to shame. The force is absolutely staggering and devastating when a pressure vessel blows and this is quite similar. People who work around big pressure vessels, respect them and are afraid of them, for good reason. It's mouth dropping how it shreds metal like a cheap soda can, when just someone's average 10 or 20 gallon garage compressor blows. Some shops, keep them in separate rooms, with concrete walls, for good reason. The bigger they are are the harder they blow up and shops use some big ones, I would do the same, they are no joke. I've heard horror stories of unmaintained ones, that filled with water and rust. Luckily someone wasn't killed by them. Utterly rotted out and the only thing saving people from grave injury or death, was all the rusty gunk at the bottom, that had managed to somehow freakishly stop it from blowing up. The best thing to do is have one with an automatic drain cock if it's big. And for small compressors, leave the cock open after you drain it and tilt the tank towards the hole if it is offset from the bottom like some are. Get all that water out, so it doesn't rust the tank. Never use combustible oils greases etc. around high pressure air, even PCP airguns have killed the odd person or injured them from using the wrong oils or greases. And that's just a small tank on a rifle, but it's upwards of 2600psi and can go higher on some of them, like 3000psi. It's like a grenade and absolutely has killed people.

[@Edward.Rippett.]

His accident seriously made me open my eyes about safety while shooting

[@joemoment-o1275]

Absolutely fine video.

[@paulnelson2362]

It's nice to see an educated gentleman make a clear and honest analysis of Scott's accident. I really enjoy Scott's videos, and now I've found another firearm KZbin channel to subscribe too. See you in your next video brother.

[@GearHeadBoris]

Very interesting. I learned a lot from this especially the recommendations to reduce the effects of a catastrophic failure. Rex reviews is saying the overpressure may have been caused by using a muzzle brake with those particular rounds. At the end of the day thank god Scott is recovering.

[@jeremiahm3765]

"Sorry for all the non-binaries" 😂

[@gblackburn31]

Let this be a lesson on eyewear safety! Ol Scott would be a pirate today if had not been for his safety glasses. So if you dont wanna be a pirate...put'em on ARRGGHHHHH ME LADDIE!

[@misturchips]

Thank you - I had the same question about venting the cap, and making it a bit thicker to increase mass. As far as WHY the ammo could have failed, there is a clue: IT's old military surplus, so it could have been treated VERY roughly, causing the powder to shatter / become a smaller grain size with more surface area exposed to flame. This would cause a considerably higher burn rate / impulse peak. Glad he has made it through the critical bit of time, and hope he's back in full force soon!

[@joesinakandid528]

An excellent, excellent analysis and evaluation sir. May I make a small suggestion - In your hands-on evaluation you may wish to check those threads as closely as practical. IF (!) prior firing cycles weakened or degraded the cap's thread structure then the cap, on that last shot, could have had a degraded thread structure going into that final cycle. The next to the last shot was with a "hot" round (again, the military does not countenance any "Hot Rounds" in their inventory) which could have almost stripped the cap threads going into the subsequent cycle with the 'really hot' round at the end. As with most 'postmortems' here we only have the presented facts --- however, the base of the last round, if it was recovered, may hold some clues as well. All the best in the search for what really happened. - TSgt Joe - Ret. USAF Munitions

[@RedTSquared]

Good God that was a great explanation of what happened. Thank you for sharing your knowledge with us!

[@Kickstandsup83]

kzbin.info/www/bejne/l6PHqGNviJx6nKc

[@101_skeleton6]

Maybe make the 2 tabs longer to add strength and make them less likely to go flying?

[@dannygame8381]

I don’t think think longer but wider at the base so it’s harder to shear off

[@Nickrioblanco1]

The type of ammunition that caused the failure was a SLAP cartridge this type of ammunition was tested in the .50 cal and the 7.62 x 51 in the 7.62 version it caused catastrophic barrel failures due to in-bore break-up of the sabot. I believe because of the age of the ammunition he was using the material of the sabots was compromised causing the projectile to become lodged in the barrel and obstructing it. You may also note in the video these rounds exhibiting great inconsistencies in their point of impact. This can also be explained by the defective sabots.

[@jtqthetieman]

You mentioned exactly what I was thinking about, engineered modes of failure or engineered fail points. This rifle, as designed appears to have three primary weak points, breach cap threads, cap tabs, and the hinge. This reminds me of over pressurized Beretta 92 pistols chucking half of the slide at one's face. It wasn't a common issue but, search "Beretta 92 slide failure" and you'll find a few examples. For the RN-50, I say beef the lower and those tabs up until they can hold the cap on without threads at 175% to 200% pressure then design the hinge connecting the upper and lower to shear at 150% pressure and check to see if it will blow the whole upper forward with blowing chunks backward.

[@garrystreeter-noaafederal2049]

When purchasing bulk surplus ammunition, would you recommend weighing each round to help eliminating hot or suspect rounds?

[@jay2ssrstt]

If this accident was due to reloading the cartridge with the wrong (fast burning) powder the weight would still be correct so weighing would miss that. If this was old powder degrading or repeated shipping of the rounds mechanically breaking up the powder to smaller particles again the correct weight would still be in the case. The answer is if it's suspect just don't shoot it. Weight is a good check if you're reloading as you can see a discrepancy between your cases in event you under or over loaded one and you know what the correct weight should be. You can't know the correct weight or what powder is in them when purchasing a few rounds of rare ammo so even if they are all the same it doesn't guarantee safe.

[@psp1921tsmg]

You didn’t address firing a sabot (slap) round out of a gun with a muzzle brake. Which is a strict no no

[@mathy4605]

Depends on the muzzle brake. If it has the same diameter as the rest of the barrel, it shouldn’t destabilize the actual projectile.

[@theoopla]

I too would like to see this aspect addressed. I was given to understanding that a muzzle break can cause a sabot to fracture, which could lead to a barrel obstruction.

[@jic1]

@@theoopla But that couldn't have been the cause in this case, because the previous round was an API. I understand that the main danger with firing a SLAP round with a muzzle brake is potential fragmentation of the round and the brake, not kabooms.

[@SavvygeMediaGroup]

Damn, very impressed by your video on the subject. 'Excellent explanation, very in depth. You really deserve more subscribers. '

[@Killer_Space_2726-GCP]

Very well explained! Videos and breakdowns like this are why I'm subscribed, and will stay subscribed.

[@btd7477]

Tibasaurusrex had the thinking that shooting sabots through a muzzlebreak eventually caused the over pressure......great video

[@thomasmiller8214]

Rex is right about this! Anything in the barrel or blocking the barrel will cause overpressure. I had a small elephant grass seed fall into the barrel of my 375 Ultra Mag while on a hunt in Africa. The seed is thin and flat and it caused quite a bit of over pressure when fired at an animal. The sound was deafening and the blast knocked my hat off. Missed the animal though the sights were dead on, so no telling where the bullet went. The barrel was fine probably because I had it cyro treated when built.

[@btd7477]

@@thomasmiller8214 Doesn't take much......I have even heard of condensation inside the barrel causing issues.

[@jic1]

Mark Serbu's initial statement on the accident: kzbin.info/www/bejne/a3K8Z5x7i819e5o

[@johnleca]

Great analysis, humble, professional, based on information at hand. Impressed, thanks.

[@tangoechodelta4156]

Very well done. Clear and well presented. You just randomly came up in my suggestions and you earned yourself a subscriber.

[@hornyducks4090]

Mark serbu himself will be doing an autopsy on the rn50 used

[@jacktheaviator4938]

This is like a Dr investigating accusations of malpractice against himself. If Serbu wants his future customers to have any confidence in his products, he needs to have all of the examination and investigation done by a third party who doesn't have a vested interest in the results. When talking about what equates to a pipebomb going off in your face, the public deserves nothing less.

[@Locahaskatexu]

@@jacktheaviator4938 I disagree with your assertion of "This is like a Dr investigating accusations of malpractice against himself" respectfully. The sense that I got from Serbu in the vid that he made is that he wants to see what went wrong and how he can use that information to improve his design and prevent things like these from happening in future.

[@avlawns3037]

@@jacktheaviator4938 I'm sure you will come back when Serbu shows transducer data over 90k and eat your words, right?

[@garyclarkiii730]

The 9 dislikes were probably troons upset about the female thread comment

[@David-py7os]

get a sense of comedy jeez

[@graemesim40]

Thank you for an excellent engineering and analytical review of the incident, hopefully the checks carried out will bear fruit and identify the exact cause, but I think you are spot on in your commentary thank you again, for both Scott and Mark have had some strange posts on this incident, yours shows reason and thought along with sound engineering 👍👏

[@squibblez2517]

Fantastic video! You can very clearly understand all the info presented, and it is very clear you are very good at what you do. Hats off!

[@DanGoodShotHD]

You deserve so many more subs my friend. Well done.

[@maymayman0]

Great video

[@blackhornedmountainchicken3720]

Extremely interesting, glad you posted this as it cleared up a few questions I had so thanks for that.

[@homer97027]

Thank you for the well described explanation. My RN-50 went from the front of the safe to way in the back. It just moved 7 spaces toward the front again. Thank you.

[@ragnarragnarsson3128]

If it were mine, I wouldn't shoot it until the failure analysis by Serbu is complete. He may end up recalling them or offering additional safety measures.

[@lumpyzx2645]

Finally someone else who isn't blaming the rifle, the rifle itself is safe, that ammunition unfortunately was not, thankfully Scott made it out alive and should hopefully make a full recovery

[@shaneebahera8566]

the rifle isnt to blame but almost anyother 50 cal would have had fail safes in place

[@lumpyzx2645]

@@shaneebahera8566 any other rifle would have blown up as well and seriously injured the shooter

[@shaneebahera8566]

@@lumpyzx2645 we dont know that unless you actually run tests with the same ammunition but my point is most rifles have design feature to reduce the chance of a serious injury or death in the event of a catastrophic failure the rn 50 has none of that.

[@AC-ld4np]

"Sorry to all the non-binaries out there, but threads can only be male or female"- classic

[@abonynge]

The SLAP round was designed for the Marine Corps. The Marine Corps does not allow the SLAP round to be fired from the M107 due to "hazards". The plastic sabot acted similarly to a barrel obstruction greatly increasing the chamber pressure. The cartridge he used is not supposed to be fired from rifles, and as such the lack of research into the cartridge itself is the flaw here.

[@TheJuggtron]

Thanks for the explanation. One question I have is, what would this round have done in a different mechanism, like a bolt action or self loader?

[@jacktheaviator4938]

I would really like to see the failure testing (if any was ever conducted) on the RN-50.

[@This_Account]

Mark Serbu said he was going to do that on his KZbin channel.

[@jacktheaviator4938]

@@This_Account sorry, but failure testing performed by the manufacturer isn't exactly the best option to convince people after one has already gone off like a bomb. Smells a lot like CYA. For the prices he is charging, he could definitely afford to have a couple destroyed, by an independent third party. And he doesn't have the equipment to test it properly. Unless he is hiding an electron scanning microscope somewhere. Otherwise, there is no way to tell if the heat treatment of the parts was done correctly. And traditional 60° threads are notoriously hard to heat treat, that's why most gun makers tend to use a buttress or "acme" style thread, especially for a part that is gonna be screwed on and off every time the rifle fires.

[@BloPsy__]

@@This_Account He is going to do that? Wow, that's amazing. So they test catastrophic failure after it almost killed someone, not before? Shouldn't you do such a test before you put the product on the market?

[@ScottKenny1978]

@@BloPsy__ when a gun malfunctions, every manufacturer wants to see it to see what happened. Every. Single. Manufacturer. This is normal. Also, pressure spec for .50bmg is 55kpsi, proofing spec is 125% of that, 68,750psi. Getting those threads to completely strip out like that requires over 85kpsi, which is 155% of design pressure spec. There was something seriously wrong with those SLAP rounds.

[@BloPsy__]

@@ScottKenny1978 Great, but shouldn't they do such a test before they release the weapon? To see how it behaves when everything goes wrong? To maybe include failsafe features that could try to ensure three projectiles are not thrown back at the shooter, two of which literally act like bullets? Because it seems that no such test was conducted with the RN-50 before. I mean, even car manufacturers do crash tests to find flaws in their design to try to make the car safer - for the cases where everything goes wrong, so you at least have a chance to live.

[@Hansengineering]

It was a hot round, yeah?

[@ThunderChunky101]

VERY!

[@MAGAMAN]

It was a hot round, but what made it deadly is the poor design of the gun. in a 5o bmg, it might have damaged the gun, but probably would not have been nearly as bad.

[@Hansengineering]

@@MAGAMAN did someone die?!

[@iamwisepotato]

@@Hansengineering almost

[@Hansengineering]

@@iamwisepotato oh ok so not deadly, then.

[@dwarden3]

I've had a similar incident with ammo from an unknown source, my ar blew apart in my hands and face. Thankfully I was wearing glasses that saved my eyes. My hands and both arms have small scars to remind me to never use unknown ammo again. Glad that Scott is doing well, and hoping for a speedy recovery!

[@cowthedestroyer]

It is not recommend to feed your ar 300 blackout as this enrages the gun

[@DoNotPushHere]

I think the stuff about the threads does help in case of accident. Yes, only the first threads carry the standard load, but in case of overloads, more and more threads start to work because of the same deformation that happened to the first 4 ones working. Even more, if you only have 4 threads working but many more "to spare" the load will get distributed before the first 4 deform to a destructive point. My two cents but that's also how preloades bolts work in construction. The bolt is "overloaded" to a preset point to make all threads work at the same time

[@VTPSTTU]

1:53 You have already said something that is completely wrong. We don't know that the only thing that can cause this failure is a single and massive overload. Threaded connections fail regularly as a result of fatigue fracture. Unless someone does a real metallurgical failure analysis on this piece, we cannot know whether this connection failed as a result of fatigue or simple overpressure. Liquid metal cracking can also cause failure, and we need to know what thread lubrication he was using. We need an analysis done to see whether that lubrication or some component of that ammunition caused liquid metal cracking. 3:00 We cannot rule out the possibility of something being wrong with the RN-50. We don't know whether the cap or the barrel was made of the proper steel. We cannot rule out either the cap or the barrel being heat treated incorrectly. Those issues can only be determined by doing a complete metallurgical failure analysis. 3:20 Threaded connections fail all the time in the threads. Sometimes, they fail in the threads because stress concentrates there and starts fatigue cracks. Sometimes, they fail in the threads because the threads are cut incorrectly. Anyone who has done any amount of legitimate engineering failure analysis knows that threaded connections are the source of many failures. Video of a single tensile test on a single threaded connection failing in the threads does not prove your false assertion. Your assertion that the rifle is not the reason for this failure is false. I don't know how rigorous the design really was, but even a good design will fail if fabrication was done incorrectly. This video is doing a great disservice to the shooting community by spreading false information.

[@MetalMasterdom]

I'm with this guy ^^^. Bad gun. Bad design or badly made(with bad parts). Makes no difference. I would NEVER shoot one after seeing what happened there.

[@donkeystonky5362]

Well put, and I don’t see why all these people are kissing Serbu’s ass so hard. While that round could have possibly caused catastrophic failure of just about any rifle it was put into, the way in which the RN-50 failed was especially dangerous, as shown by Scott’s injuries. When they were developing this thing, they should have considered how it would fail in such a situation, rather than just assuming that it would be strong enough to not fail. The ears that prevent it from firing out of battery could have been made better. If they were instead extended the length of the receiver/frame, then they would not have gotten blasted off toward Scott. Instead, the force might have sheared the pivot pin that holds the barrel to the frame and launched the barrel forward, which might have been a safer way for it to fail. Scott said that Serbu told him that it would take 85000 psi to shear the cap threads the way they did, so assuming that’s accurate, and based on a normal chamber pressure of 55000 psi (60000 is also normal for certain loads), that means a factor of safety of 1.5454, which is not very high when the only failsafe of this rifle is the hope that it will be strong enough to never fail in the first place. It’s not a bad design because it failed, it’s a bad design because of what happened after it did. While the argument has been made in this comment section and all of the others that it would be unreasonable to over-engineer everything to the point that it cannot possibly fail, it is very reasonable to design things in such a way that when they do fail (because they probably will), they fail in a way that minimizes the damage done by that failure. For example, Top Fuel dragsters used to have the engine, clutch, and driver positioned in such a way that if the clutch exploded, the driver’s feet or legs could get cut off or damaged. The result of this was not making the clutches weigh 500 pounds so they were so sturdy that they would hardly ever explode, the answer was to reposition the driver so that when the clutch did explode, they would not be in the path of it.

[@lupettoversilia]

2:19 *non* =====🚂=========

[@Steve-om4iu]

?

[@MrRiftman]

That was an absolutely awesome analysis. Broken down to where somebody with limited knowledge of physics can understand it while still being succinct, descriptive, and to the point. Well done! I know quite a few college professors who could learn something from your presentation style.

[@johnfoley3633]

You suggested putting a gas vent hole in the cap itself. Actually don't many rifles designs, some going back to at least WWII, have gas vent hole (or two) drilled into the cartridge area of the barrel as such a fail safe? If the cartridge is overpressure, the brass will tear at the vent hole releasing enough pressure to prevent the failure of the barrel or the breach. The added benefit of that design is that the vent hole is pointed straight up so it's in the user's line of sight but not pointed at his face.

[@Liberty-Freedom-Outdoors]

This was my exact question to the manufacturer why come no vent holes like most rifles

[@ScottKenny1978]

Not all rifles have vent holes, though they do all have safe vent paths. Pressure spec for .50bmg is 55kpsi. Proofing spec is 125% of normal, 68,750psi. Getting those threads to strip off like they did required over 85kpsi, 155% of nominal max pressure!