How Rims Prevent Rifle Blowup!

[@jamessotherden5909]

I don't believe I have ever read or seen someone explain the difference between the different types of rims. Well done sir.

[@jamesonoakes6816]

The reason that the semi rim was kept on the 220 Swift was because it’s parent cartridge was the 6 mm Lee navy. When 6mm lee navy became obsolete because of the adoption of 30-40 Krag Winchester had hundreds of thousands of pieces of brass lying around, instead of dumping them or putting them into the smelter, they decided to use them and just neck some Brass down to the .224 caliber creating the 220 Swift. Necessity is the mother of invention, Yankee ingenuity triumphs again.

[@RonSpomerOutdoors]

Thanks for the additional history, Jameson!

[@jk-kr8jt]

Jameson, that is great info. Thanks, for the knowledge. I always suspected it was so that Winchester could offer a hotrod without having to rework the bolt face and extractor on the M-70. Almost as you can't get a number of bolt actions in 223 because of the smaller bolt face. Thanks again for filling us in. Cheers, Jeff.

[@funkla65]

@@jk-kr8jt yeah, that is part of the story, too. The Lee Navy didn't have much of a rim (.448 vs the .445 base dia), but Winchester bumped up the rim to fit a standard .473 bolt face. They also did basically the same thing on their ill-fated replacement for the Swift, the 225 Winchester.

[@jk-kr8jt]

@@funkla65 thanks Larry. Good info. I never think about the 225 win, actually I don't think I've ever seen that cartridge. For some reason I think the 225 died before it ever got to the starting gate.

[@funkla65]

@@jk-kr8jt yeah, the 225 pretty much did just that. The 22/250 was so popular by then that Winchester should've just conceded to it. Keeping the 220 as an alternative offering would've made more sense than trying the 225.

[@larrysayers1377]

A very good explanation. Always bringing up good topics that are not discussed in other videos. I started off big game hunting in the early 70’s and here in Western Canada my first rifle was a 303 British. I recall my dad showing me how to load that clip in those old army surplus rifles in that I had to keep the flange rim ahead of one another to ensure a smooth feed.

[@44hawk28]

The model 102 model 88 were not inventions of Winchester, they were copies of the Sako finnwolf and Sako finnbear. Which were Superior rifles in every way except that they were never chamberd in .284, which is probably one of the finest overall cartridges ever designed.

[@camdeskjockey2355]

The rain on the .225 Winchester always intrigued me as to why it was done that way.

[@KevinMn1]

I’ve read and enjoyed your columns for years but finding your KZbin channel really adds so much to the content. Keep up the great work!

[@mikereese15]

You never cease to amaze me with your in-depth knowledge of ammo and cartridges.

[@404nitro]

Ron, the 450 Bushmaster sitting there also headspaces on the case mouth just like the 30 Carbine and 350 Legend.

[@ShidenByakko]

I heard the shape of the .375 H&H Magnum is due to the propeller which was at the time, long-extruded-rods, which resulted in long shallow shoulders. That necessitated the belt because there was no way to headspace on the too-shallow shoulders...

[@DrBreezeAir]

That’s correct.

[@kevi152]

Cordite strands, but that’s not entirely true. Cordite strands are not that long. What is universally accepted is that conical cases are easily extracted when the brass splits. Cordite is quite a bit more explosive in the tropical sun. Indeed the reduced loads for the tropics was written on my Holland rifle case before it was eaten by termites. I only used the case during transport and fortunately one of the earlier 375 h&h from 1914 is still going as accurately as on its first day. One of the reasons why I never found the need for a 30-06.

[@ShidenByakko]

@@kevi152 I heard something about the reduced loads too. But unless I see the source, not sure about the rest....

[@thefeatheredfrontiersman8135]

I just bought a new caliber. 450 bushmaster, can't wait to look at the round itself after watching this video.

[@danielcurtis1434]

Sorry Ron the 1899 savage wasn’t the first lever gun with a non tubular magazine. You seem to forget the Winchester 1895!!!

[@sylviajones3355]

Now we have the .277 Fury. (6.8x51) with a brand new type of rim/case construction.

[@MrJtin69]

Very interested in that hotrod

[@sylviajones3355]

@@MrJtin69 It does look interesting, but It seems like it will be more expensive than most of the ammo we have now.

[@jaydunbar7538]

Performance gain for all the extra fuss is not great, very inefficient. If you just have to have every fps possible regardless of cost then sure, but for most of us if we want that extra speed just getting a bigger cartridge is the more effective way to go.

[@glockster157]

The one I never understood is the 375 Winchester. Much higher pressure than the 38/55 but they made it shorter! So you cannot use 38/55 ammo in the 375 but you could chamber the 375 in the 38/55.

[@magnumcipher4971]

The .450 Bushmaster headspaces from the cartridge mouth as well.

[@shanerolfe8022]

Get segment Ron , as always. I have loaded over 8,000 rounds of 375 H&H magnum over the last 38 years, and I was told to headspace on the belt , I could only get 3/4 reloads before they would split at the shoulder from full length resizing,. I started neck sizing only, people said I would destroy my rifle, or would not be able to chamber the rounds.🤔🤔🤔 I managed to get 30 reloads at top velocities with 225 grain projectiles. I found with neck sizing I could get nearly 10 grains of the slowest burning powders extra in them, without any excessive pressure. I could get velocities of 3100fps.. though I’m am paying for it now, my neck and shoulder are frozen solid, I also have had at least 50 stitches and a couple of surgery’s on my right eye socket😢 the joy of being a professional shooter🤣😂🇦🇺🐊

[@DrBreezeAir]

Good God. Did the rifle explode on you?

[@luvtahandload7692]

You're hilarious!!!! 🤣🤣🤣🤣

[@seanmacdermott6555]

Another thing about the 450 Marlin is that the belt is longer than most belts. This is to keep the 450 Marlin from being chambered in something like the 8mm Remington magnum. The relatively short 450 Marlin will fit in the 8mm magnum chamber but the longer belt won't let it chamber all the way. The bolt won't close. Another safety measure. I own a 459 Marlin and found it to be an interesting cartridge. Perhaps one day you can do a full review on it.

[@splashmonster18]

Variations on rim thickness have a lot to do with the cartridge's intended use and weapons platform, the nitro express rounds were typically used on game, in mostly very well built rifles that have extractor/ejector engagement approaching 1/4 of the rim diameter, the 45/70 500 Government was designed for battle, in a trapdoor rifle that has a much smaller rim engagement. The same can be seen in Remington rolling blocks and the Browning designed single shots.. Another outstandingly presentation Ron!

[@georgesakellaropoulos8162]

Perfect preface for a discussion of headspace.

[@coreyrowe2052]

Always a mountain of knowledge from this man!! Thank you Ron for doing the research. So the layman can learn! We appreciate you so much!!!

[@johnmollet2637]

Great video Ron! Always like seeing people trying to educate our newer shooters and I am especially glad you hit on the 450 Marlin's belt. I would not have remembered it if I were doing the presentation, I guess that's why you're the Pro. Great Job!

[@robertdufresne9195]

Do I see a 375 HH mag. there?. You have some interesting cartridges. Looking forward to seeing your show. 🇨🇦

[@tlloyd9325]

I really enjoy these type of podcasts. I would venture to say those of us that hand load and are a little bit older like the information. It is fascinating that you’re taken the time for the research required. Thank you Mr. Spomer!!!!!

[@tatsuhirosatou5513]

There have been a few rifle rounds to headspace off the case mouth, 30 carbine, 50 beowulf/12.7x42mm, 450 bushmaster that all came before the 350 legend and there are some weird round like 7.62x54R and 303 brit that have rims but headspace off the shoulder because of their use in automatic weapons.

[@duanesamuelson2256]

The 7.62R and .303 Enfield have rims because they were originally for bolt action rifles. For commonality of ammunition (making logistics far easier) part of the requirements as the machine guns were developed was to use the same round. Thanks for giving the information on how they headspace, I have been casually curious why people have so much trouble sourcing MG ammunition for the .303 that fires reliably. It's highly dependent on country of manufactor and at this point I'm guessing that it's a case wall thickness issue (light primer strikes) and not head spacing correctly. Even moreso since the same sourced ammunition fires reliability in rifles.

[@Bearandsonsgunworks]

fun fact: The .225 Winchester Is an improved version of the the .219 zipper (parent case 30-30 win) which has had the rim trimmed from .506 to .473 to accommodate a standard boltface same as. 30-06, 308 win, 7mm mauser, 6.5 swede, etc.

[@joelmcmahan7386]

Thanks again Ron for sharing these great post of outdoor adventures and the tools we all have a passion for using. Your knowledge in outdoor life is fun and informative to hear and see. Wishing you and yours the best from me and mine. 🎥💯👍

[@frankgagas9569]

Thank you Ron for the great explanation. I never knew what “headspace” meant until I started reloading. Your video increased my knowledge of this topic

[@johnh4957]

I fell for the idea that belted magnum was for strength and newer versions increased inner brass in that area instead of a belt, now I know better, thanks. Interesting what developers have to do for safety or commonality.Very helpful having actual cartridges for comparison, I'm a visual learner. Was the evolution of metal casings also influenced by shotguns?

[@slypperyfox]

Headspacing is one of the more complex topics that face new shooters and reloaders. You could do a 30 minute intro on that. I had heard somewhere in the past that the belts on cartridges was to assist “feeding” and not to strengthen the case. The feeding assist wasn’t equated to headspacing so this helped clear up a fuzzy spot I had. And Dave Peltz is a huge fan of rebated rims and between his explanation and yours this topic is also settled in my mind. Keep up the good work. I subscribed, clicked on the bell and joined your patreon acct today.

[@leonhsmith3646]

Love the 284 Win. My father has a Winchester Model 100 in 284 that is a phenomenal hunting rifle. My brother and I have Model 100s in 308, also good rifles. Haven’t found a decent 243 to complete the collection yet.

[@randysimonneau8182]

I could not have said it any better Ron! Well done! Its all about headspace and SAAMI specs.

[@laredoland]

Thank you, Professor. Well done.

[@lloydryan7716]

Proof that we always keep learning, thanks Ron

[@popman10001]

So great! Thanks rob for another great pod cast a little sad I missed it live. From your friends in the north 🇨🇦

[@coltonwinkler5473]

Love learning new things! Well done Ron!

[@jonathanhoup9988]

Always a wealth of knowledge Ron! Great content on this channel

[@GatorFlash1]

Good presentation. I would like you to do one that explains the price differences between today's cartridges, and why. Cheers!

[@troy9477]

Great presentation. I knew most of this, but it is always good to have a refresher. I expect to see more rebated cartridges in the future, given the emphasis on short, fat powder columns that we have now.

[@1madmaxx80]

Another great presentation! Very informative 👍👍

[@bigheadred3528]

Awesome video as always! I love the 350 legend. Factory ammo out of a savage axis. A really cheap rifle is the best shooting gun in my safe. And I love the ballistics for whitetails is southern Ms

[@mikenorton62]

Another great video Ron... Thanks!

[@zechnarwilliams8019]

Very informative sir, I love hearing about different cartridges and how they came about and how they work!

[@aaronwilcox6417]

That 348win is just pure sexiness, and the model 71 rifle is the schnitzel too. Got a few of them.

[@jonrolfson1686]

For my part, at least, the Model 71 rifle sold me on the the .348 Win cartridge. Upon arriving at the shop one day I saw a Browning branded Model 71 on the consignment rack. Testing the gun for fit showed that it came effortlessly to the shoulder like a properly fitted double barrel shotgun with the sights already aligned for my right eye. Kudos to whomever proportioned the wood for that rifle.

[@tonnywildweasel8138]

Fascinating stuff! Thanks once again for sharing solid info, appreciate it a lot. Greets from the Netherlands 🌷, T.

[@chrisaerts6489]

Very educational. Thanks Ron

[@jeanmorin3247]

So interesting! Thank you!

[@owennikish7995]

Great video again Ron👍! Another rimmed cartridge myself and I'm sure alot of other's would love to see you do some of your reloading numbers on is the old 303 british. A great cartridge that really gets overlooked by the manufacturer's. Choices for for bullet types and weight are very small buying from manufacturer's today. It's a 30.cal but uses slightly larger bullets than the typical. 308 . It would be awesome to get some info about reloading this great old cartridge! It's amazing to me how many people still hunt with the 303 and old enfield's up here in Canada. They just work for anything!

[@MrTacklebury]

One word you might have used is headspace. The 30 carbine does also headspace off the mouth of the cartridge as does .45 Colt in many firearms. They do have a very minimal rim on the .45 colt, but most revolvers have the cylinder reamed just so the mouth does the headspace. I have a .45 colt/.45 acp Ruger Blackhawk and the .45 acp cylinder works that way also. Many lever guns needed the rim for extraction, due to their design.

[@daveknowles3055]

Good one Ron found it fascinating and once again your explanation made it easy to comprehend

[@franzschmid9079]

Hi Ron, perfect pronounced "Flobert", yes, it is French! Great info's as usual! regards from Switzerland

[@RonSpomerOutdoors]

I guess I had a flair for Flobert.

[@GMdrivingMOPARguy]

450 Bushmaster is also a rebated rim straight wall, it headspaces on the case mouth

[@SniperC175]

Love your vids. Rims are also necessary for extraction.

[@44hawk28]

The very first fully contained cartridge Firearms were designed in 1808 and was offered to know other than Napoleon, and he rejected it because he would have had to carry extra types of ammo. Could you imagine what Waterloo would have turned out if he had cartridge firearms. After Napoleon rejected cartridge Firearms, there were actually a few cartridge shotguns made in that era, the idea fell out of favor for some time. But then again we are talking about the French. If you look at the inner workings of a lever action tubular fed magazine you will see that it requires a rim to manipulate the round into the chamber. It's part of the mechanism that allows it to get onto the elevator which lifts the cartridge in order to be able to be put in the chamber.

[@troy9477]

That eas my thought, but then you have the 35 Rem. I don't know if the lifter and bolt are different since it is rimless. I have never owned a 35 Rem, although i would like it in a 336

[@johnwnuk506]

Great job as usual Ron . I was thinking that the Midwest straight wall deer cartridges need a good though video I know that they are out of your normal selection but they are a staple in states that require them . I believe you touched on the 350 legend and 450 bushmaster before. But some history and ballistics on the Main ones like 44 mag, 350 legend, 450 bushmaster, 45 raptor, 50 Beowulf,460s&w, 500 s&w. Exe. I think it would be a big hit that every Midwest deer hunter would enjoy allot.

[@paulsimmons5726]

Mr Information! Great stuff, as always!

[@sakostwwy1903]

Excellent video and expertly presented. Enjoyed it.

[@willnotquit]

Awesome info…thank you!

[@randallkelley3600]

30 carbine 350 legend, 450 bushmaster, 50 Beowulf, and nearly all auto pistol cartridges headspace off the mouth.

[@luvtahandload7692]

You could put it that way. You could also say that, at least some of them, they headspace off the extractor. That's why a .40 S&W will sometimes fire in a 10mm pistol.

[@fruitfarmfords8243]

.450 BM headspaces on the case mouth too

[@jk-kr8jt]

Thank you, Ron. In 16 minutes you gave an extensive history of the cartridge rim and headspacing. Where were you 40 yrs ago when I was trying to figure all this out? The Swift was always a bit of a puzzle to me. The rebate on the 284 was just plain cool when I was a kid. I think (that'll be trouble) the first rebated rim, was on the giant 500 Jeff case. But you did say US rabated cartridge. I've often wondered why the 284 Win didn't spawn a bunch of offspring and wildcats. Do you have any input on this? As much as I dig the Hornet it can be a pain in the magazine. But so can a 30-40 Krag or a 303 Brit. Mindful loading takes care of that. Keep well, Ron. Cheers Jeff

[@GoldCountryTrapping]

Great stuff Ron.

[@RatelLaw]

Thank you for sharing

[@richardl69]

New hunter here. I noticed you mentioned 8mm Mauser, I've watched most of your videos and like them, I don't recall seeing much on this 8x57. Do you have any information/video on this cartridge?

[@kurtreinhardt6789]

Thanks for the info Ron

[@squib3083]

Another fantastic video thanks!

[@ShinnahWilde]

Thanks, Ron!

[@randallkelley3600]

The first centerfires look like rimfires. They weren't drilled/punched through primers. I once found a centerfire, non drilled through primer case while camping in the Badlands of North Dakota.

[@georgesakellaropoulos8162]

Without a hole in the web, how does the primer ignite the powder charge?

[@randallkelley3600]

@@georgesakellaropoulos8162 The primer was placed in through the mouth or before the case was completed. They basically were still manufactured like rim fires, but the primer was placed centrally. The early 45-70 cases, and others, were hollow head not solid head designs. It’s difficult to actually put 70 grains of black powder and a big 500 grain bullet in modern cases.

[@BitteNurEINFormular]

For having the belt on the cartridge, there may had been another Intention: H&H built the first Magnum hunting rifles, all based or built around the Mauser 98 system. As you know It’s a controlled round feet action, that, in countrary to the push feed action, it does not have this steel ring at the face of the bolt enclosing the head of the cartridge (with only a little gap for the small fixed extractor) The crf bolt head is much more open. So i guess, with the higher pressures at that time and low experience, they feared that the cartridge can break and blow out at this point around the head. So they mounted the belt as a kind of insurance. Really required or not, lateron it became the synonimus for heavy and strong calibers. (Roy Weatherby „took over“)

[@user-cs1ne8gx9u]

Great work, thanks

[@AdventureswithaaronB]

Can u make a video on hunting with ar for beginners

[@OntarioBearHunter]

the 450 Marlin is nice in the Ruger No1 if you can find one.

[@matthewblumenthal804]

Loved it! Thanks!

[@carlosspicyweiner7734]

I believe the M1 carbine headspaces of the mouth and I know the .450 bushmaster headspaces off the mouth as well.

[@russelljackson7034]

Right on

[@lloydshultz9645]

Great information.. thanks

[@kevi152]

425 westley richards was rebated ! I’m sure there must have been other rebated rims before the 425 but it’s the only one l have used , albeit in a side by side double .

[@wayneblair288]

The 450 marlin got 11Thou Belt so it won't go other mags like 7mm.

[@randallkelley3600]

If I remember correctly, its the same width as the Weatherby belted mags.

[@forward1165]

Thanks for another interesting and informative video! I have a question though. About the 1899 savage with a box magazine. Didn’t the 1895 Winchester come out first?

[@bj2294]

Always informative.

[@gizmocarr3093]

Rebated rims have one issue to consider. When the case diameter exceeds the smaller diameter face of the cartridge. This increases the pressure applied to the base of the cartridge. It makes less surface area for case pressures to be distributed on the base of the cartridge. What happens to some cartridges that are necked down to smaller-bore sizes is the pressures rise past the limits of the rebated rim face. After firing one shot, the primer will fall out of the cases showing the effects of excessive pressure and ruined for further use. The 6 mm 284 wildcat cartridge had a serious problem of it happening. However, Roy Weatherby designed the 460 and 378 cartridges with enlarger cartridge faces that made these two cartridges the most powerful ones of the time. He could have easily made them without belts just didn’t. Winchester Short magnums used this idea without a belt with a larger case diameter and cartridge base. The bolt and receiver have to be fit for the larger diameter cartridge. That is a reason other rifle makes shy away from making rifles for them. The cartridges are improved and better. However, because fewer rifles are made for the cartridge doesn’t make it bad it just makes for fewer rifle choices. ✨🦉🔎✨🙂

[@hs459]

great video,, like the info,, Thanks

[@thomasfowler8645]

Ron, can you comment upon the rimmed .303 round? Used extensively around the world, and effective...?

[@damonmulnix6356]

220 swift was based on a now obsolete round called the 6mm Lee navy which had the semi rimmed design so they just kept it

[@dr.froghopper6711]

Great video Ron!

[@funkla65]

Another piece of the 45-70 vs 450 Marlin puzzle: the rim (or belt) diameter of the 450 Marlin is smaller. Therefore, Marlin could use a smaller diameter magazine tube, which impinged less on the space for the barrel and reduced metal removal from the receiver, thereby producing a stronger rifle.

[@davewinter2688]

In a falling block rifle such as the Ruger Number 1 or Siamese Mauser which is a '98 action, a 45-70 can be loaded to drive a 400 grain bullet to over 2000 fps with pressures over 50,000 psi. Warning! Do not try these loads in your Trapdoor Springfield which is limited to 28,000 psi or your 1895 Marlin or modern built 1886 Winchester which will take pressures somewhat higher pressures than the trap door. Otherwise you may end up rimless, beltless, faceless or headless. All the major manufacturers keep their 45-70 ammo below the SAAMI MAP of 28000 PSI but recently there are some outliers producing significantly +P 45-70 high velocity loadings that could be on the shelf by the standard cartridges. Like Ron says in another video, PAY ATTENTION TO WHAT YOU'RE PUTTING IN YOUR GUN!

[@sebastianhabel7312]

Nice video, I used to think belts on cartridges were solely safety features to prevent them from being loaded in guns that were not designed to handle their pressures. But can't you get the same problems with belted cartridges that you get with rimmed ones when they are staggered in box magazines? Is there anything like "belt-block"?

[@dasbongo1740]

You tend not to as belts are much thicker than the thickest rim.

[@comentedonakeyboard]

Rimmed cartridges are also easier to massproduce, at least that was the reasoning behind the 7,62x39s rim.

[@NomadicHacker.]

Great video..i was honestly getting a little tired of the "best cartridge" or "old obscure cartridge beats modern cartridge" videos they are interesting but I am enjoying the variety

[@meccastreisand2722]

Rims on bottleneck cases that exceed maximum body diameter cause the bullet come out of concentric alignment with the primer of the next cartridge in tubular magazines. I don't know if this was a deliberate design element, and I kind of doubt it for a number of technical reasons, but it is a factual effect.

[@georgesakellaropoulos8162]

This, combined with a groove around the outside of the primer pocket is how the 8mm.Lebel avoided the problem of a pointed bullet setting off the cartridge ahead of it in a tubular magazine.

[@leroynelson4717]

I wonder what would happen if a 45/70 managed to be fired in a 450 Marlin magnum rifle? I understand that the H&H style belt wouldn’t let a 450 chamber in a 45/70 but what about the other way?

[@44hawk28]

4570 in modern rifles was driving 300 350 grain bullets for flight quickly. And could take heavy powder charges. The problem was what happens if somebody gets the wrong ammo and puts it into a trapdoor or some other older rifle. That was all the thinking that went into the 450 Marlin. It had nothing to do with rocket science, it had everything in the world to do with keeping people from being stupid.

[@NvincibleIronMan]

Hey, Ron. What plaid shirt is that?

[@lonniemiller4078]

What twist rate do you think I should have to stabilize a 250 grain boat tail hollow point in 338 Lapua Magnum (Hornady match bullets)

[@averyabood6155]

250's are tolerant of either a 10 or 11. Do a 9 and shoot 250 and 300. My last two have been 9 twists and have shot the 250 equally well as the 300.

[@georgesakellaropoulos8162]

@@averyabood6155 I was going to suggest 1 in 9, but you beat me to it lol.

[@j.m.castillo9561]

The comment on the belted cartridge was wrong. It works fine on Mauser action but Mauser rifles/cartridges pre-date the belted cartridges. They introduce the belt because of shoulder collapse (with big long cartridges) in chambering which results in hard extractions and/or head separations. Hence, having the belt as the headspace solves the problem that big long cartridges have in trying to headspace from the shoulder.

[@elgato9534]

Factory ammo. The cheap stuff for belted magnuns from Winchester Remington headspace on the belt. I would get ugly black rings on once fired brass! Premium ammo was fine.

[@NickFrom1228]

Savage model 99 came out with a vertical magazine? I thought it came out with a rotary then after several decades came out with a box magazine.

[@RonSpomerOutdoors]

Yes, Nick, but a rotary magazine stacks cartridges one atop the other -- a vertical stack, but circling around the center spindle of the magazine. No bullet tips against primers of a round in front of them.

[@NickFrom1228]

@@RonSpomerOutdoors Thanks Ron. Makes sense I guess. I think it is the engineer in me that couldn't something rotary as a vertical stack. Since it is more about the magazine change from tubular to other that it ties in better.

[@bwfreel]

Ron Please, big bore lever guns ! 45-90 etc.

[@gunman-6646]

I wish you could still get .223 wsm.

[@thehoneybadger8089]

They all have rims. "Rimless" is a misnomer. What is missing on cartridges like the .30-30, .45-70, .22lr, etc. is an extraction groove.

[@RonSpomerOutdoors]

Yes, nicely summarized, HoneyBadger.

[@georgesakellaropoulos8162]

Yep, exactly what I was going to say.

[@donaldslayton2769]

Proper magnums wear a belt, lol

[@garrett892]

Made me scratch my head on the 30/30 to think if it headspaced on the rim or the shoulder.

[@leskrug9266]

I have my 4570 government in a Marlin 1895 cowboy action 26in octagon barrel, my bullets are traveling at 2250 fps no signs of any pressure, 300 ftp mag.!