How Does It Work: Roller Locking

/ forgottenweapons
www.floatplane...
Cool Forgotten Weapons merch! shop.bbtv.com/c...
Roller locking is a system that is not used in many guns and often confused with roller-delayed blowback - which is understandable, given the similarities between the systems. Roller locking is really a sub-type of flapper locking mechanism. It was most significantly used in the MG42, and also in the Czech vz.52 pistol. In essence, it uses rollers in place of flaps to lock the bolt and barrel securely together during firing, and depends on an external system (short recoil, in the case of the MG42 and vz.52) to unlock before it can cycle.
Contact:
Forgotten Weapons
6281 N. Oracle #36270
Tucson, AZ 85740

[@lucajohnen6719]

I would have loved a side by side comparision between the two systems. I do know what the difference is now (Locked needing a seperate action while delayed is still just blow back) but it would help with a visual aid.

[@mattisvov]

Me too.

[@PetrHosek]

kzbin.info/www/bejne/iKnQgJSjnNeJg9E Ian already gave one 7 yrs ago :)

[@kamiskub7409]

@@PetrHosek wow thanks! This comment should be pinned or sth

[@inhuman4]

@@PetrHosek Thanks for the link!

[@JasonsDeathCurse]

Me too but ya know what I’d really love? To see Jesus at like a frat party. Wearing a white Tee shirt, yet on the Tee Shirt is a picture of a black tuxedo & bow tie. Can you see it? The big man, JC at a huge party, chicks all around him, a frosty cold Budweiser in one hand, the other hand on some frat boys forehead forgiving him of all his sins. Yet all while rocking that sweet bow tie tuxedo white Tee shirt! That’s what I wanna see! See, it makes JC look like the real deal all while seeming quite approachable! No man bun! Christ let’s his shit flow with the wind, ya know!

[@coreytrevor6906]

Good to see my old friend, the CZ 52 Slide Face Man.

[@edged1001]

Gun Jesus mentions "Roller locking is rarely used in practice". What are the disadvantages/advantages of this system?

[@jonasstrzyz2469]

My guess would be ammunition sensitivity? And the fact that the AR system has had 50+ years of development so from an RnD standpoint designing a new roller locked firearm is probably more expensive. Although, in a gass gun, I do not see how ammunition sensitivity would be an issue.

[@shawnr771]

Disadvantages would include more complicated and costly production. Depending on the overall reliability of said firearm possible increased costs for repairs and training for users and maintenance personel. Purchasing a military firearm has extended costs of maintenance, for the service life of the pistols.

[@RussianBlue4S]

Because it still requires a short recoil system (in a pistol) or a gas system (in a rifle) and so you essentially gain nothing over more traditional systems like Browning short recoil or any other rifle action. If you want rollers, the real win is being able to go to Roller-Delayed Blowback which eliminates needing a gas system altogether.

[@shawnr771]

@@RussianBlue4S Thanks.

[@TheFanatical1]

You can accidentally make it work when it fires out of battery slightly and then you can do away with moving barrel, which reduces component wear I suppose

[@Kbaker45862]

So where is the rest of that mg42 Ian. Don’t be holding out on use man.

[@alecjones4135]

It looks it's from a pistol

[@Kbaker45862]

Alec Jones 1:34 in that bolt and barrel are from a mg42.

[@BleedingUranium]

@@alecjones4135 An MG 42 pistol? I want one!

[@rolfnilsen6385]

@@Kbaker45862 Or an MG-3 ;-)

[@Kbaker45862]

Rolf Nilsen good point I never thought of that.

[@caboodlebricks6930]

The mailman just delivered your book. This turned out amazing!

[@crazyfvck]

@Caboodle Bricks I agree! I received my copy yesterday :)

[@rtg]

Just got mine as well. Awesome!

[@loyp4328]

0:44 that lock seems very surprised

[@turbowolf302]

You will never unsee the face in the CZ-52 locking group.

[@longboweod]

"Oh NOOOOO!" it seems to say.

[@screamsinrussian5773]

aaaaaaaaaaa why did you have to do that

[@matthayward7889]

Why do we still not have FW branded “universal disassembly tools” available to purchase? I’d love one!

[@Kumimono]

Flapper Lock? Sounds like a dance from the 20's. Er, 1920's....

[@F1ghteR41]

Given that Degtaryov designed it back in the 20's, your joke gets even more points.

[@alecjones4135]

More videos like this 1-5 minutes explaining the basics mechanics. I came here for the history of the gun but stayed because I love to learn about the how the gun works.

[@TheFanatical1]

Oh thank god, I was only just yesterday thinking "how the heck is the MG42 actually a locked-breech gun, when it looks just like a roller-delayed system!" Truly Ian is the hero we need, even if we will never earn him.

[@paullim706]

The Mg42's barrel assembly moves under recoil, locked with the rollers to the bolt carrier, until it reaches the end of its designed travel where there process to unlock as described by Ian takes place. OTOH, the G3, CETME, MP5 and so on have fixed barrels.The bolt is not truly locked to them Roller delayed blowback acts as an extension of a blowback action as the name suggests. The rollers act to delay the open of the bolt by temporarily concentrating recoil forces acting on the bolt carrier as a whole into the rear portion of the bolt carrier assembly. If the rear portion of the bolt carrier assembly has ( by way of example) half the total mass of the bolt carrier and is constrained by the rollers to move 3 times the distance as the front portion of the bolt carrier ( real world ratio are higher than this), The rear half of the bolt carrier must experience 3 times the acceleration. If Force= mass* acceleration, bolt weighing 1 unit of mass experiencing one unit of acceleration needs to have 1 unit of force acting on it. OTOH, 0.5m*a+ 0.5m*3a= 2f. Thus even though this bolt carrier weighs only 1 unit of mass, with the roller delay system, it requires a forces similar to a bolt carrier twice as massive to experience the same acceleration.

[@Thisguydoesstuff]

Clean, concise, and informative. Great breakdown Ian!

[@dashingdave2665]

Accurate Brief Clear

[@deanbuss1678]

Been a gun enthusiast now for about well forever. This is new to me. Genius engineering.

[@mattisvov]

I adore these explanation videos. Seeing as almost all I know about firearms I know from watching forgotten weapons. (When I started watching, I didn't now what a "bolt" was, but by watching countless videos, I was able to deduce as much.) The channel is obviously aimed at a more knowledgeable audience, But it's nice when Ian throws us greenhorns a bone and explain the basics. :)

[@highlandoutsider8148]

Watching those rollers engaging and disengaging is so satisfying lol

[@jenerik_guy2474]

PLEASE keep doing more of these, they're so interesting

[@Beborda]

Love the How It Works series, Ian. Brief and easy to digest. Great content as always! 👍

[@crazyfvck]

I just want to say that I received my copy of your book yesterday! :) I received an email saying it was delivered, and I couldn't wait to come home from work and open up the package. It is GORGEOUS! You guys did an amazing job, and you should be very proud. Thank you dude :)

[@markgordon4368]

That teat emptied out far too quick 😂😂

[@ratagris21]

On the CZ52 the rollers have to be replaced somewhere between 250-500 rounds because they wear easily. I have one and replaced them with modern rollers compared to stock, but its a good side note to be aware of.

[@ZGryphon]

Ah, good old vz. 52. Handsome from the slide rails up, but with all the grip ergonomics of a paperback book. :)

[@72polara]

I got my copy of Chassepot to FAMAS yesterday. Very impressive work my friend! The color photo from 1917 on page 141 is amazing, so clear and sharp.

[@BananenBread]

MG42 VIDEO CONFIRMED

[@rarbona]

I got my book yesterday! Thanks Ian the quality is amazing!

[@muneer3240]

Thank you, I’ve been wanting an explanation of this for some time; and as always, thanks for the quick and easy video!

[@Aaron_Jensen]

Awesome, I was literally thinking to myself yesterday how I'd love for roller locked firearms to be the next highlight in this series.

[@SlimRhyno]

I absolutely love this video! Is there any way you could do one on "radial delayed blowback" system that CMMG has developed? I'm sure you have plenty on your plate as it is, but seeing a technical comparison between both the radial delayed and the roller delayed would be incredibly interesting... and I am sure that I'm not the only one who thinks so. Thanks, and please keep doing what you're doing!

[@RalphReagan]

Thanks for posting this.

[@KuruGDI]

Really interesting to see that Pistols also had a roller locking mechanism. I only knew that system from the german machine guns and it's derivates.

[@Bloodreign137]

KuruGDI snd it’s such a fun gun to shoot! You can pick them up surplus for under $300, you can buy every part on it brand new for super cheap, and mags are $8

[@KuruGDI]

@@Bloodreign137 I live in a country where I can have two Pistols. Every further one has to be authorised by the government and costs a ton of money. But still, I would be very interested in the gun as such!

[@Mildcat743]

I'm so glad we got a little tidbit video today so I could watch it before I cracked open my copy of your book.

[@SgtKOnyx]

No, I did still have some confusion after watching both of these, fortunately someone in the replies to a comment shared an old video of yours (the HK P9S I believe) and that video contains the part I was missing. Specifically in the explanation that in a roller delay system force can be applied to the rollers and they will unlock, whereas in a roller locked system the rollers cannot unlock from force applied to them. Thanks @Petr Hošek

[@wastedangelematis]

so simple and easy to undertand, we missed the ROLLER coaster ......

[@timothysvec8568]

I saw your in Forbes. Well done Sir. Well done!

[@loupiscanis9449]

Thank you , Ian .

[@hdexotic1914]

had to watch this, i’m in the bundeswehr and we are learning about the mg3

[@jimchambers7548]

Short and to the point, thats what i like👍👍

[@dewuisscantlebury936]

this was informative, thanks... been wondering for years and this is the simplest explanation I have seen so far

[@xenonram]

You've been wondering for years, and you've never looked it up? When I wonder something for 6 seconds, I pick up my phone and type, "how does a roller delayed blow back system work." I don't know how people can go so long wondering about something, without looking it up. I guess it's because I went through the first 15 years of my life while the internet was in its infancy and there wasn't a ton of info on it. You had to find someone who knew the answer to a question, and take their word at that answer. It's crazy how many things I grew up "knowing," only to find out they weren't true. People could act like they were super smart, because they could tell you an answer to a question, and there was no way for you to check their answer. We had a volume of encyclopedias (actual books), and then we got a CD rom version of _Compton's Interactive Encyclopedia by Encyclopedia Britannica_ in the early 90s for our Macintosh. It was revolutionary at the time. Way before Wikipedia.

[@stinknut762]

Reminds me of when i didn't study for an essay in school. I'd give a super basic, vague report but still technically give the info.

[@kmech3rd]

OK, I understand the locking system- that makes sense. The driving system (inertia/recoil) I don't quite get yet. But I'm halfway there. Thanks, Ian!

[@MrGdg1969]

Thank you Ian. I think it would be a good idea to compare different systems of locking such as rotating bolt, roller locking, tilting bolt, locking flaps, vertically-moving locking blocks etc. I understand that such a video cannot be short. :) Why in 40th and 50th tilting bolts were popular (Bren, SKS, FAL) and after that most popular rifle families uses rotating bolts (AR, AK)?

[@wingracer1614]

Rotating bolts have some very real advantages in the accuracy, strength and durability departments.

[@sabertoothray]

Whats the reason for the lack of use? overly complicated? difficult to maintain? more expensive to produce? Thanks for the video, love learning stuff like this.

[@micahholley1446]

So I feel like there was a massive argument over these two systems under one of the previous videos, so Ian is settling it. Anyone else get that vibe? Regardless, this was a super helpful video!

[@vascurten]

yeah, please gun jesus, give us more, this one was way too short (but still great)

[@al_lahn4264]

I've often wondered why the roller locking mechanism isn't more commonly used in pistol designs. It seems to me that it would naturally reduce muzzle flip compared to Browning-derived tilt locking designs or rotational force from a rotating barrel locking system like in a Beretta Px4 Storm. The roller locking system is one of the reasons why I like my vz. 52 pistol so much.

[@Lindeman08]

It has answered some questions but left others. Why is it uncommon? What are the up/downsides? This could definitelty have been a longer clip and still kept my attention.

[@neutronalchemist3241]

It's more complex than a tilting action, and it has more surface friction, so needing more lubrication.

[@mohhamedofthefirstworldjer7488]

Would love to see some more videos about firearms design from this viewpoint. I would very much like to see how the mechanisms work and the different schools of thought on the matter. Side by side comparisons too.

[@ForgottenWeapons]

I have a whole playlist of these...

[@mohhamedofthefirstworldjer7488]

@@ForgottenWeapons oh bother, this is one of the first I've seen in my feed.

[@ManOnTheRange]

i love my CZ52... especially in 9mm luger... it have some problems with very light 9mm loads (birdshot for example wich CZ75 eats perfectly) but +P and +P+ is perfect... and for the record it uses 9mm overpressure for most of its civil life as a secsufull target pistol with single slide :)

[@tetlow2]

Have done a video on roller delayed blowback. I'm interested in seeing that

[@ForgottenWeapons]

That's next week.

[@tetlow2]

@@ForgottenWeapons cool beans. I'm looking forward to it.

[@sejembalm]

How about a video on the difference between roller locked firearms such as the Czech CZ 52 pistol, German MG42 and Rheinmetall MG3 machineguns, and roller-delayed blowback firearms, such as the HK G3, where there is no genuine locking of the bolt and no recoiling of the barrel in delayed blowback actions?

[@ForgottenWeapons]

Next week is roller-delay.

[@dougwilliams8602]

I had one and sold it. It was fun

[@eldsprutandedrake]

I like these short How Does It Work, would like to hear more about advantages and disadvantages though! An idea for a topic that I always wondered about is hammerfired vs strikerfired, I mean I get the main mechanical differences but I don't really know why you would chose one over the other in eg. a pistol.

[@ifell3]

Fantastic never knew there was a difference and was on pistols!!!

[@stone9302]

I love the CZ 52, such a cool gun.

[@KSPilo]

1:01 MG42 / MG3 Bolt.

[@galengond8251]

More MG42 - the MG3 Bolts that i have seen are finer worked.

[@Martinlegend]

im still waiting for a video about the mg 42

[@bramster-b9v]

This is already quite a complicated locking mechanism, but I see the similarity to the rollers delayed system.

[@AlexG1020]

I ended with more questions than I came with

[@billbolton]

Thanks, great visual demonstration, very interesting.

[@RyeOnHam]

If we did not have roller LOCKING we would not have roller-DELAYED locking. As the story goes, German Engineers discovered that roller-locked guns would operate themselves under the right conditions. Then we got the CETME.

[@martin2514]

We all love flaps. 👌👌👌👌👌👌

[@thelizardking3807]

Now we need roller delayed

[@edi9892]

Please make a video on felt/perceived recoil. Why does the G3 hit harder than the FAL? Why then use MG42 and Barrett mechanisms with even more mass moving? What can Kriss and AK101 really do?

[@RockSolitude]

I would like to see roller lock in wider context of the gun. Its difficult to grasp its operation of the gun as a whole (and how such a system might apply to other weapons given you are showing a pistol and talking about a roller lock as it might apply to a pistol) when its only a zoomed up shot of the roller locking assembly itself.

[@johnmitchell923]

Cz 52 is the best looking gun ever

[@drewren1231]

Me: pfft I know about roller delayed blowback. Ian: roller locking is not the same as roller delayed

[@kongandbasses8732]

I know roller locking systems from the H&K G3. It is a verry reliable system.

[@mahartma]

You missed the entire point of the video, if you're not attempting a lame troll. The G3 is not roller locking, it's roller-delayed blowback.

[@alistairmscott]

Anyone else think his channel should be called "Forgotten Weapons with Gun Jesus"?

[@Iceidice]

Mg3 bolt?

[@tema_buraz9029]

Or mg 42, one of the 2

[@forestalfrank1074]

@@tema_buraz9029 Or MG 74

[@Axonteer]

And i just rolled forward into this video and im totally locked to mr gun jesus

[@markfergerson2145]

Just watched the video on the failed Colt offering. What was with the slots in the back of the slide on that thing? Were they not expecting the sand/saltwater soak test?

[@PatGilliland]

Very informative, Thanks!

[@polishcrowbar9969]

I wouldn't have thought that this system exists in a smaller version than the MG42/MG3, actually it kinda looks cute in the pistol :D What about the reliability of this system in the pistol?

[@pulsar1-1]

What if you used blocks (like traditional locking lugs) instead of rollers, 8m working on a design that does that and is long stroke gas piston operated and I was wondering what other people think will happen. I am very much still in the concept drawing phase and I'm looking for feed back.

[@Schmunzel57]

Would the roller look allow use of black powder more easily than other self loading mechanisms?

[@jimscharba4818]

Great video, very informative...thanx

[@malvahasan1658]

Also du bist großartig mit einem sehr großen G :)

[@mahoganyballs2296]

These are great instructional vids. I wonder if you would consider an addendum including examples of the most common firearms using each different system. Great Channel! Keep up the good work. Also I love how it's always about the guns and not about the politics.

[@werfer5]

you are totally wrong about the MG42/3/1 bolt. Nothing is pushing back the carrier (except the rollers themselfs). On recoil, the barrel is pushing back the bolthead. The rollers (they are not allowed, they are forced in), therefore ar pushed against some bars (I don´t know the exact term in english) in the receiver, witch force them into unlock. BTW I like all your videos (everything but the french stuff)

[@davejob630]

How odd. I had an add. The tube is sneaky!

[@phnompenhtrader9698]

“Rarely used in practice” only in the Special Forces weapon of choice for SAS and around the world then,the infamous Heckler and Koch MP5?

[@candidmoe8741]

Will this system works if the weapon is solidly attached to a 100 tons unobtainium block (indeformable, indestructible)? What makes the central piece move back? The whole gun recoil?

[@armadagunshow]

Very interesting, thanks for sharing 🎉

[@morganahoff2242]

0:44 Anyone else see Edvard Munch's The Scream?

[@jonhedrick7440]

Congratulations on the article in Forbes

[@ForgottenWeapons]

Thanks!

[@jonhedrick7440]

Anytime I watch your channel more than I watch t.v.. you guys are the best

[@jonhedrick7440]

I hope y'all come to wv like y'all takes about on in range. I live in the eastern panhandle. If y'all so come I'll be there with my ar

[@allanbador7316]

blish lock function please !

[@vincenmt]

Shame about the Cz52 de-cocker. Mine hasn't worn down yet. Not looking forward to the day it is.

[@Bloodreign137]

I got to fondle my CZ52 while gun Jesus handled one on screen and I think that’s the closest I’ll ever be to one of these videos lmao

[@sackychin6267]

Can you do roller delayed blowback and/or tilting breechblock (FAL) next?

[@jelmore9898]

That pistol is for sale in my local shop...

[@DjDolHaus86]

What's that little screw thing on the front of the trigger guard on that pistol?

[@ForgottenWeapons]

Disassembly gripping surfaces.

[@DjDolHaus86]

@@ForgottenWeapons thank you

[@Jarris2]

This finally answered roller locking, still don't fully get how roller delayed locking works.

[@tommasomorandini1982]

I don't now how many people this is going to help, but it seems like some have a hard time distinguishing between locked and delayed systems. So, imagine pushing with a rod on the bolt face throu the barrel: if it opens, it's delayed, if it doesn't, it's locked.

[@neutronalchemist3241]

A short recoil action (Browning, Beretta/Walther, or that CZ...) opens that way. Simply the barrel recoils with the slide for the first few mm.

[@tommasomorandini1982]

@@neutronalchemist3241 I didn't thought of that, not the best rule huh?

[@neutronalchemist3241]

@@tommasomorandini1982 Nor you can make the rule "it's a delayed blowback if the bolt moves, but the barrel stays still", because in a Revelli action (today used by the FN Five-Seven and the Ruger 57) that's considered a delayed blowback, the barrel recoils, but at a slower pace than the bolt.

[@IronMan-yg4qw]

great info. but to short. Can you do a video on the inertia locking system as in the Benelli Inertia Driven Operating System?

[@gregoryadkins2213]

I can’t find on you tube regarding the Roller Delay on the PTR-91,ala H&K’S in 308.

[@hotrodhendrix1]

Gun Jesus new groove. The "Roller Lock". Roller roller roller and Lock. Like Michael Jackson but better

[@francislematt7079]

that's actually a Steyr MG74 bolt, isn't it? It's heavier = fewer rpm

[@8076A]

Is there any particular reason this system doesn't see more wide-spread use? It looks fairly simple to manufacture and maintain over-all, It seems like it would be reliable due to its simplicity and few moving parts. Looking at the example guns shown its clearly an older design but it could likely be improved upon with modern technologies, after-all roller-delayed blow-back was designed in WWII and is still used today, although primarily by HK to my knowledge. Then again I'm a sucker for unique designs, would love if companies did limited runs of older model firearms, there's a kind of novelty to them even if they are unusual in nature.

[@TheKlink]

What about that ball-bearing-lock from that straight-pull hunting rifle from however long ago?

[@ineednochannelyoutube5384]

I would say any flapper locked system where the flappers are not captive, and have a curved surface is a roller locked one.

[@Taolan8472]

Answers to questions i didnt know i had. I figured the difference was marketing.

[@chocolateniklas7845]

Do you have a video on that pistol?

[@TJWDawg]

kzbin.info/www/bejne/rHaokqaPeb9-e6c He does.

[@chocolateniklas7845]

@@TJWDawg thank you