Rem Brass - case seperation
 

I had a 4 time loaded rem brass seperate just above the belt in my 7mm rem mag the other day while busting a yote. Bullet hit the intended target but exctration of the case was difficult, it ended up seperating leaving the remaining portion in the chamber but when I removed the bolt and tipped it up the case fell out. At the shoulder it has crimple marks and powder burn where I assume the seperation took place. A scope shows no effects to chamber or bore according to my gunsmith. Test fires at the range proved everything is normal and where it should be. Load has shot fine for a couple of years, no pressure signs and this is the first time such a thing has happened to me.(have seen it on the range before just not personally). Powder is RL22 same lot number as previous.

Got me thinking about brass and sizing technique. I was taught and still FL size my brass. I inspect the brass prior to reloading and always work up with different components even though a load may be proven previously. I rarily tumble anymore, just wipe them down and reload. Think I am being particular about my reloading techniques but when something like this happens you wonder just a tad??

RE: Rem Brass - case seperation
 

4x loaded brass does seem like a short life expectancy for that round however finding one bad casing in a lot shouldnt worry you, especially with Rem ;)Now if all of them start doing it I would change brass and see if it happens again, then I would doubt something in my reloading process.

RE: Rem Brass - case seperation
 

Stop FL re-sizing, too much working of the brass. i do not load 7mm Mag. But i getseven or eight loadings from my .300 Win Mag and moderate loads. Heavy loads are another story.

RE: Rem Brass - case seperation
 

Since this is a one time occurence,it sounds like a bad case rather than a problem with your loading procedure.I full length all of my hunting loads,and have not experienced this although I use fairly hot loads.

RE: Rem Brass - case seperation
 

Crimple marks at the shoulder? How far are you bumping the shoulder back, when you are resizing? Tom.

RE: Rem Brass - case seperation
 

I wouldn't worry too much about a single occurance. I've always felt that Remington brass is a little more brittle than that of others, such as Winchester, etc, and can cause cracking in the head/web area earlier on.

RE: Rem Brass - case seperation
 

The generally accepted norm for belted magnum cases is to only trust them for hunting up to the second reload. After that, they are subject to case seperation at any time. There is a lot of history on how this case design came into being and why it is still with us today; but the bottom line is that it was considered, at least from an initialdesign standpoint, to be a non-reloadable case.

RE: Rem Brass - case seperation
 

FYI, a pic of the Rem case in question.

RE: Rem Brass - case seperation
 

Not my rule.I often hunt with cases loaded five times or more.

RE: Rem Brass - case seperation
 

I know some belted magnum loads incertain guns can have fair brass life, if you have a fairly tight chamber and only resizethe case justenough just to touch the shoulder. But overall, belted magnums are not a very reloadable design. I'm personallywouldn't considergoing to Alaska or Africa with belted magnum loads based on brass that has been shot four or five times. I'll save those cases for load development and target practice, and trust my once-in-a-lifetime hunt to new or once fired brass.

RE: Rem Brass - case seperation
 

I would love to know where that shot went when the case ruptured. My bet is that it hit low somewhere. I feel the rupture may have caused some of the gases to move forward to the shoulder area of the chamber where they were sealed off by the casing itself, causing the dents in the casing at that point. The argument to this may be that the vent ot the side of the receiver should have handled the gases from the ruptured casing. That's a thought, anyhow............what do you all think??

RE: Rem Brass - case seperation
 

I was deer hunting whenI bumped a coyote the shot was running straight away80-100 yards and I took him out inbetween the shoulder blades DOC. I aimed base of the neck though being off hand can't be sure if I dropped it or your theory is right as it hit lower. Never really gave it any thought till I went to eject the spent case and it gave me resistance. Like i said first time it happened to me so was bit pannicked and took the gun to my smith as precaution. Once he gave me a clean bill I stopped at the range and fired 4 groups yielding typical results with the same load. 5 of the test shots fired some were with 4x loaded brass same batch as this one &the others were on3x loaded brass and different lot#. All Rem packaged brass BTW.

Roskoe, I pitch my brass after the 5x loading, again the wayI was taught with other than standard carts.

Since I need to re-stock my brass for the 7 rem mag, any suggestions? Locally Rem is the most readily available but winchester can be found earlier in the year with ease. Though not opposed to mail order either.

RE: Rem Brass - case seperation
 

looks to me like the die is set too low. Crumpling the brass.

RE: Rem Brass - case seperation
 

It will continue to happen, regardless of the make of the brass you are using, BECAUSE:

Your rifle has a "generous" chamber, and your cases are stretching a little in head-to-shoulder dimension on firing each time. You then push the shoulder back on resizing, and every time you fire it, it stretches again until the brass becomes fatigued and cracks-then it leaves the front part of the case in the chamber while the head is extracted! Belted (and rimmed) cases have this problem a lot.

The solution is to set your resizing die out a little, so the shoulders of your cases stay put when you size the brass. You can't really prevent the new cases from being stretched once, unless you go through the drill outlined below with new brass. But you CAN prevent it from happening again and again. If you feel a need to "full-length size" each time, "smoke" a lubed case with a match or candle, screw the sizing die out one thread, then screw it back slowly, testing it each time you turn it in slightly, until the shoulder inside the die just barely touches the case shoulder, then lock the collar at that point.

Personally, for brass fired already in my rifle, I only size enough of the case to get a firm grip on the new bullet......

IF you wish to totally eliminate this problem, starting with new cases, youexpand the case mouth up to .30, or even .338, caliber, then neck it back down to 7mm in increments very gradually, creating a "false shoulder" on each case that you adjust for headspace by checking it in your rifle's chamber as you continue to size it back down, stopping the sizing process when you reach the point that you can JUST BARELY close the bolt on the case with some force. You size all your new brass this way, and you end up with a bunch of funny-looking cases, but ones that are prevented from stretching on firing the first shot by the false shoulder you created to compensate for the slop in your chamber dimensions. I know this is a PITA, but it is the same process you have to go through when creating wildcat cartridges, and it will absolutely prevent case loss due to stretch.

RE: Rem Brass - case seperation
 

Welcome to the world of Remington brass. The only Rem brass I use is 260 Rem, because it's the only factory brass currentlyavailable. Nosler will produce it next year! I'll order 1000 rounds the day they're available.

I average4 of 20 Remcases every time I fire, that have split necks.And it's not even near a max load. I average 10 of 50 right out of the bag that have oversized primer pockets.I have some Winchester 243 brass that I necked and trimmed that works just fine after more than 10 loadings.

RE: Rem Brass - case seperation
 

The problem you are having is caused by full length re-sizing. Adjust your die so that just enough of the case neck is re-sized to hole the bullet.

RE: Rem Brass - case seperation
 

Thats news to me. R-P has never had a issue in any of my rifles. Especially not 4/20!

RE: Rem Brass - case seperation
 

As far as case stretch goes, smoking a fired case and setting the resize die as Eldeguello suggested should take care of the problem.
As far as the dimpled case goes, from what I got out of the original post, the case was NOT dimpled before firing due to the die being set excessively low. If this was the case, all or most of the cases would have exhibited it before firing. The dimples appear to have occurred in the chamber upon firing and the case rupturing.

RE: Rem Brass - case seperation
 

[quote]ORIGINAL: Pawildman

As far as case stretch goes, smoking a fired case and setting the resize die as Eldeguello suggested should take care of the problem.
As far as the dimpled case goes, from what I got out of the original post, the case was NOT dimpled before firing due to the die being set excessively low. If this was the case, all or most of the cases would have exhibited it before firing. .The dimples appear to have occurred in the chamber upon firing and the case rupturing.[quote]

Most likely rom low chamber pressure due to gas escaping when the case ruptured....


(I've been using R-P, Winchester, Norma, and GI brass now since about 1954, and believe me, they all make some bad stuff once in awhile. Case neck splitting is due to lack of proper annealing. If this is happening with R-P cases, just anneal them before you load them. I've never had any R-P cases with oversize primer pockets - but I have foundsome WW cases that had off-center flash holes. (In factory -loaded .375 H&H ammo......)

RE: Rem Brass - case seperation
 

Yep. As far as neck splitting goes, which really didn't seem to be a concern at this time for the poster, annealing is a fairly simple operation and is covered by some of the reloading manuals. The older Lyman books described it, I believe, for one...........

RE: Rem Brass - case seperation
 

Thanks for the advice. Though do find it odd thatI have yet to experience it in this rifle, it isn't new and have been reloading it with rem brass, same techniques for several years.

No the dipples weren't there prior to firing:eek:! I assumed they were a result of the seperation in the chamber.

RE: Rem Brass - case seperation
 

I have been thru this several times over the years, shooting magnum wildcats cartridges. The demples in the case were casue by the head seperation. The gas flowed foward around the outside of the case and was sealed off somewhat by the shoulder, causing the demples.

You can check your brass for signs of future head case seperation by taking a paper clip straighten it out long enough to reach the bottom ofthe case. Bend the end to be inserted in the case mouth 90 degrees with a tang of about 1/8" inch. Drag the up and down the inside of the case from the bottom up to about half the case. You will feelan indention of the about 1/16-1/8" above the belt if the case is starting to burn thru. If you feel this indention or ring inside the case, scrap that piece of brass.

RE: Rem Brass - case seperation
 

i never had a case break like that,but i have had those same dimples in both rem and winchester brass in 22-250.i found the cause of it was this stupid x-sizer die i bought from rcbs.i switched back to a normal die and the problem was solved.i guess i prolbably had a different situation though.

RE: Rem Brass - case separation
 

skeeter7mm,

Sounds as if this is the first time that you've experienced case head separation. Well it Will almost knock your socks off. It take your eye out and is one of the best reasons I can think of for wearing shooting glasses.

It's almost unbelievable how many things have to happen, in order, for that case head to separate. First of all, while I don't care for Remington cases, the brand of your cases had nothing to do do with the separation. I haven't read all the replies you've gotten, and if I step on anyones toes, I apologize. Please believe me that it was nothing personal.

1. Case head separation is an example of head space problem. Either the nut who chambered the rifle was lose, or the nut who adjusted your sizing die got it too tight. I wish I had a dime for every belted magnum case I've neck sized in the last 50 years plus or so. I've always neck sized only. By the time chambering became a problem, I replace the cases, andthis usually got me about 8 to 10 shots per case. Those shots were full power loads. I have a target shot with 68.5 grains of IMR-4831, 140 grain Sierra #1910, CCI #250 primer that won a month long 3 shot, smallest group contest. The groups were fired from a bench at 200 yards. My group measured .581" to win the 4x scope division. Another target of the rifle was with the 150 Sierra SBT, CCI #250, 68 grains of IMR-4831 with a velocity of 3087 fps. Four shots measure .198" at 100 yards. Still another target for the same 150 Sierra SBT, same powder and primer for a velocity of 3124 fps that measures three shots at .098". It just so happens all three of these targets were fired with a 7MM Rem. Mag. M-700 Remington rifle. All were neck sized cases, but it was with threedifferent rifles.

2. Once the firing pin strikes the primer, and before the powder starts to burn, the case is driven as far forward in the chamber as it will go.

3. Once the powderstarts to burn and chamber pressure starts to climb the thinest part of the case starts too expand first. Since the thinest part of a case is at the mouth of the case, it expands first.

4. A ring of brass moves up the case as the pressures increase and come in contact with the chamber wall.

5. Until the demand that the case expand due to increasing pressure fails too matchthe ability of the brass to keep up with the rearward movement of the case head. Then separation occurs.

6. The case cannot move rearward in the camber due too it being held in place by gas pressure.

7. Once separation occurs, chamber pressures start to drop. But it is not uncommon for escaping gas to mess things up a little first. With reduced pressure the front of the case shrinks, allowing gases to flow between the case and the chamber wall which results in those dents you found and why they were so sooty.

Sounds like a wholelot of stuff going on in a very short time doesn't it?
I hope that this is of some help.