I have shot lots of “machine gun” brass over the years. Sized it down to 7-08, 243, and various wildcat chamberings with no head separation as of yet. I shoot it in several bolt guns, an M1A, and a CETME. Do I ever get oversized fired cases? You bet! I don’t know what other die brands are like but my 45 apc sizing die doesn’t have a decap stem and a piece of rifle brass will stick through the die, out the top. I just run the cases into the acp carbide sizing die and then continue to treat them just like any other fired brass, adjusting my rifle full length die for the correct headspace. Rarely is the shoulder too far back to get it right. If I run into that issue and I get case stretch it shows up quite easily during case inspection before loading. Never had a head separation or stuck case yet.
308 sizing help using bulk machine gun brass
- Thread starter P1ZombieKiller
- Start date
I went down this road too.
Imperial works great. I used to swage primer crimps, now i just cut them out with 45 degree case mouth tool on power system.
I saved myself some later processing time, i set up an RCBS Small Base X-Die. Yes you have to trim on first sizing, but once you have that done, set up the X-Die and you'll lose the brass in the weeds before you need to trim again!
MG brass can be a pain, but once you've processed them once, it's standard practices for next use.
-Mac
Imperial works great. I used to swage primer crimps, now i just cut them out with 45 degree case mouth tool on power system.
I saved myself some later processing time, i set up an RCBS Small Base X-Die. Yes you have to trim on first sizing, but once you have that done, set up the X-Die and you'll lose the brass in the weeds before you need to trim again!
MG brass can be a pain, but once you've processed them once, it's standard practices for next use.
-Mac
This is about the only once-fired brass available for 50 BMG, usually LC or WCC. It is normally way oversize owing to the loose M2 chamber, not to mention abuse at ejection.
I start out by annealing the brass. This will reduce the possibility of cracking the neck and shoulder area when full length resizing. Next I clean the brass in an ultrasonic bath for an hour at 100F. This softens the primer sealant and makes decapping possible. Then I decap with an arbor press and a pin. I full-size with a good coating of lube, and finally trim to length. Check the whole process with a Wilson chamber gauge to see that the sized brass is within SAAMI spec. and then load for firing to fire form to your chamber.
You should use a small base die if you are firing in an AR. I fire in a bolt gun and therefore I neck size only for subsequent firings, and trim as may be required. I am getting pretty consistent 5 or 6 firings from brass handled this way, but am not using hot loads. I am firing a 647 gr. M33 ball at 2800 fps. in a Barrett M99.
The 7.62 NATO brass handled this way should be just fine. Always inspect brass after firing and before reloading to insure that you are not seeing any signs of failure.
I start out by annealing the brass. This will reduce the possibility of cracking the neck and shoulder area when full length resizing. Next I clean the brass in an ultrasonic bath for an hour at 100F. This softens the primer sealant and makes decapping possible. Then I decap with an arbor press and a pin. I full-size with a good coating of lube, and finally trim to length. Check the whole process with a Wilson chamber gauge to see that the sized brass is within SAAMI spec. and then load for firing to fire form to your chamber.
You should use a small base die if you are firing in an AR. I fire in a bolt gun and therefore I neck size only for subsequent firings, and trim as may be required. I am getting pretty consistent 5 or 6 firings from brass handled this way, but am not using hot loads. I am firing a 647 gr. M33 ball at 2800 fps. in a Barrett M99.
The 7.62 NATO brass handled this way should be just fine. Always inspect brass after firing and before reloading to insure that you are not seeing any signs of failure.
Nothing wrong with using a small base die for automatics.... I use one for .308 , 5.56 and 30.06... It's not that much harder on your brass if setup correctly... Machine gun brass is famous for being messed up... Inspect each piece carefully and then resize with your small base die then inspect them closely after firing them... Your buddies chamber is a little tighter.... Should be fine after resizing.... If you don't have one , get yourself a case prep station.... Your hands will thank you....
I’m curious as to the radial dimensions at the case shoulder junction of the MG brass prior to sizing.
Any chance you have that written down?
P1ZombieKiller
Gold $$ Contributor
drop_point
Silver $$ Contributor
I use One Shot for just that...never a problem. Are you cleaning dies first and allowing it to dry properly?
Yes, I follow the instructions to a T. One shot with MG fired brass has stuck cases on me and galled dies with brass. I’ve managed to salvage the dies in all cases but have given up on its use except for sizing brass fired in my chambers.
Royal Case Lube spray has never caused me any trouble.
Royal Case Lube spray has never caused me any trouble.
drop_point
Silver $$ Contributor
I've literally done tens of thousands of them with no problems.
I do. Left over from my M1A days. Send me an email 81stfacp@gmail.com
Where in TX are you located? I am in Williamson County NW Austin
Yes. But to get One Shot to work I had to spray each case separately and that tends to waste a lot of One Shot. If you miss the bottom of the case or don't get enough on it will stick. I just found Unique to be much more reliable and easier to work with. Harder to remove but definitely easier than removing a stuck case.
That's not a knock on One Shot. I use it quite frequently on resizing my bolt gun brass.
Nick Caprinolo
Gold $$ Contributor
Ar's and machine guns produce the same problems at the base of the brass which is way you must use a small base die. The base of the case is not supported as in a bolt action rifle. It only takes a few thousands difference to prevent the cartridge from seating properly.
Insert your small base die, run it up and adjust the die until it touches the die and then give it an additional 1/2 turn so that it b umps slightly. Even brass fired from a bolt action may not seat the first time and will need to be sized with a small base die. Remember every chamber is different.
Insert your small base die, run it up and adjust the die until it touches the die and then give it an additional 1/2 turn so that it b umps slightly. Even brass fired from a bolt action may not seat the first time and will need to be sized with a small base die. Remember every chamber is different.
RegionRat
Gold $$ Contributor
This is another "it depends" situation that is far from black and white.
For the record, since I am from several generations back, when many of us had few choices but to use "unknown" surplus from military or LEO guns that were unknown to us, I can attest that the practice is not for everyone, especially if you are not familiar with the risks and have the tools and background to make it good.
Because of economics and maintenance costs, not to mention some knuckleheads that could care less, some automatics are run with out of spec conditions that damages brass badly. Some guns are considered in spec and still damage the brass. (Remember, Uncle Sam doesn't concern himself with the brass once it gets used, and many in the GOV want to stop the practice of selling off used brass or de-milled ammo components all together.)
At many points, I knew we were running some guns that needed work, but we didn't or couldn't stop. That brass was trashed and who knows where it went? Uncle Sam may surplus this brass, but they don't accept any responsibility for what happens with it or care what condition it is in.
By not knowing the details of the guns used, there is a risk that the brass is already very badly stretched. Many automatics are well cared for, but more of them than you think are not. Some have bbls and actions that trash brass and others don't.
You have only your own wits with respect to inspections you can run to determine if this type brass is worth your time. I was taught what to look for and what to reject by experts that had been doing it for a long time. That is something you have to teach while standing over a 55 gal drum of used MG brass.
This can have a very low yield, or it can be a gold mine. We had more time than money when we were young, but even then, that brass became expensive when the time was factored in. If you care about your time, or what you are doing with that brass, don't forget to run the math on your time and effort.
We have much better alternatives these days even when shortages are factored in. Unless you looked for brass and cannot find any, I would advise you keep looking.
Be prepared to correct this kind of brass and inspect it. My advice: If you are just starting out and have no mentor, avoid using unknown brass if you have an alternative that is virgin or at least from a known good chamber. YMMV
drop_point
Silver $$ Contributor
I put them in a freezer bag, spray, shake, and then dump them in a pan. I don't spray them separately. MUCH MUCH faster than using sizing wax.
I had a bad experience with cases fired from a semi-auto even though I full sized them. I broke an extractor and had to pound the case out of the chamber from the muzzle end. Also, the rims were damaged and a few wouldn't extract.
Since I get about 15 to 17 reloads out of new cases that are dedicated to a specific rifle the cost of new cases is fully amortized.
I'm not saying you can't use them, just I wouldn't base on my bad experience with cases fired in semi-auto. I try to avoid reloading problems as much as possible.
Or maybe you're just a better reloader than me.
jimsair
Silver $$ Contributor
I recently bought some "once fired LC 223 brass". It was once fired alright.... Once fired in a MG and then driven over few times with a tank. I've been reloading for decades and have never seen brass so beat up. Out of morbid curiosity, I processed the cases that were not too far gone using a small base die. They worked fine but I would not do it again. It's just not worth the time.
I did the same around then, and of all the ones I used, resized with a standard RCBS FL Sizer, something like 5-10% were unrecoverable and the rest worked just fine in my DPMS and Savage bolt guns.
It worked so well for me, I now have a few thousand of these.
I stopped shooting 308 for a long time, and so these sat.
Just built another AR10 and after a FL resizing, they still do not fit the chamber. Had to get a SB sizer, mill 5 thousandths off the shell holder, and now they fit. Figured, might as well anneal and trim at the same time.
The ones that are unusable are the cases I cannot slide into the shell holder because of base distortion from the MG. That is ~5% alone.
In terms of effort, it's a lot easier to buy new. However, the new brass I have are reserved for my 308 Match rifle.
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