Reloading machine gun .308 brass

[swift]

[smoothy8500]

Almost all once-fired LC brass is through a machine gun. Accuracy wise you are correct, it's a non-issue. Check them with a bent paper-clip for any potential case separation and treat like any other reloaded case.

[divingin]

How much shorter a lifetime should I expect relative to brass fired in a manual bolt action? Am I correct in thinking accuracy will not be affected or, if so, the difference would be minor for a non-competitor?

Assuming you got it sized to fit your chamber, there will be minimal other effects. As stated above, the loose machine gun chamber may cause some initial stretch in the case, but if it is not apparent on inspection, and you size so it doesn't get worse, it shouldn't be an issue. Lifespan will depend on how you use it more than its first firing - minimal shoulder bump, less than max loads, working the case mouth as little as possible; all these will help to extend case life.

That said, it's used 308 brass. Don't look at it like it's near and dear; it's a consumable. Use it til you can't and toss it.

[fguffey]

I have a bag of once-fired .308 lake city brass that took noticeably more effort to full-size resize than my two-times fired .308

I have no ideal how many cases are in a bag. I have purchased cases in barrels, one purchases was for 24,000 cases. There were 2 suspect cases in the lot, both were Berdan primed.

I want to know something about a case before I start, I have purchased fired cases from firing ranges, before purchasing I measured everyone of them for length from the shoulder to the case head. My favorite cases are cases that are long from the shoulder to the case head and short from the case head to the end of the neck.

I have purchased 308 W cases in lots that were too large for the bolt type shooter. Out of all of the 308W cases I have never had one that refused to be sized. Most of my case sizing has never required a lube beyond RCBS roll on. On occasion I have formed cases that resisted sizing, long before I ever thought someone would care what I was using I found a lube with no-name. I use the no-name lube to size cases with an excessive ability to resist sizing.

And then there is the unknow; that would be covered in the explanation of what happened to the case when fired. Forum members do not want to know what happens to the case when fired; forums members want to tell everyone what happened to the case when it was fired. I do not know but when I examine the case I am trying to determine what happened to the case when it was fired. FIRED IN A MACHINE GUN? I want to know what happened to the case when it was fired in a machine gun. I suggest the reloader start by measuring the case, and then I ask; who owns a bolt rifle with a machine gun barrel?

F. Guffey

[fguffey]

minimal shoulder bump

I have a leaver policy, when the case is fired and it forms to the chamber I apply the 'leaver policy'. I leaver the way I founder. Problem: reloaders are sizing cases for chamber with an unknown length from the shoulder to the bolt face. If machine gun fired cases are long from the shoulder to the case head they go straight to the top of my favorite cases because manufacturers do not sell cases to people like me. People like me determine the length of the chamber from the shoulder of the chamber to the bolt face first.. If the case is tuff to size I do not struggle with returning the fired case back to minimum/full length sized. Again, I have a leaver policy.

F. Guffey

I have never found information from a reloader that has measured a machine-gun fired case. I can not believe reloaders believe 'machine gun fired' covers it all. Reminds me of 'neck tension' that is all a reloader has to learn when typing' neck tension' that is it.

[bergmen]

Also, don't forget that military rifle brass is typically thicker than commercial brass with less case capacity. I would start with reduced loads (by a few grains) and see how they work.

Dan

[Sailormilan2]

Brass fired in an oversized MG chamber might need to be sized twice in order to get it to chamber properly. Brass will "spring back" after sizing. If it was too much oversized to start with, the spring back may be enough to prevent easy chambering.
If (IF) that happens, usually a second sizing will fix the issue. My normal procedure, if I'm dealing with known MG brass and since I'm using a progressive press, is to size using a standard die. Then use a Dillon sizer/trimmer setup, and that usually takes care of that problem. Doing two jobs at once.

[FLIGHT762]

A Redding small base body die works great on M/G brass. The die sizes the body and shoulder, no neck. Because of this, it runs smoothly through the die. I run the brass through twice (two bumps) and give the brass about 2 seconds into the die.

You will have to size the neck after this. you can run it through your regular F/L die.

[elk hunter]

When I loaded some of that stuff I had about a 50% incipient head separation at the next firing in my gas gun. I will never waste my time again with machine gun brass again.

[fguffey]

Also, don't forget that military rifle brass is typically thicker than commercial brass with less case capacity. I would start with reduced loads (by a few grains) and see how they work.

Do not forget: Reeloaders do not measure, they repeat what they have read on the Internet. When responding they go into auto response. I don't, I was told military cases were heavier and then they add the 'therefore' part, The case is thicker therefore the case is heavier. And then there is the part they assume, they assume the case has less capacity.

Many years ago I started measuring and weighing cases; My military case head thickness was .200" thick from the top of the cup above the web to the case head. And then I measured the case head thickness of my R-P 30/06 cases. The thickness of my R-P case heads measured .260" from the top of the cup above the web to the case head.

It was then I decided if there is any truth to what I read on the Internet it can only be a half truth because my commercial cases had a thicker case head than 1,000s of my military cases. And then I took the liberty to think about it.

If my Remington cases have a thicker case head and weighs less than my 30/06 military cases the case body must be thinner. If the case heads on my military LC type cases have a thinner case head than my R-P case heads my but are heavier the case bodies of my military cases must be thicker.

What does some of this mean? It means the powder column of my military cases is smaller in diameter and longer than the powder column in my R-P cases.

And with the thick case head my R-P powder column is shorter with a larger diameter powder column than the powder column in my military cases.

F. Guffey

[bergmen]

Well, my Lyman 49th edition states the following (page 219):

"Shooters should also stay one to two grains below the listed maximum charges due to the smaller volume of GI brass."

This is on the chapter for 7.62 x 51mm, 308 Winchester.

I have read this on other manuals as well.

Dan

[fguffey]

"Shooters should also stay one to two grains below the listed maximum charges due to the smaller volume of GI brass."

I believe it is a bad habit to go straight for the listed maximum charge. If the reloader knew the minimum and maximum and understood the 1/2 in the middle difference they would start 2 grains below maximum and 2 grains above minimum. I can not remember the last time a reloader measured the effect firing had on the case, I can not remember a reloader measuring the case before firing and I have never read where the reloaders stated what he was looking for.

They just want to talk about tension.

F. Guffey

[robert101]

I agree with many posts here and can relate to posts 7 & 11. I've had good results with what I thought was "machine gun" used LC brass. I don't load often to published maximum loadings and have LC cases with many uses.

[jimmykan]

If your sized brass does not chamber, try a small base die or a roll sizer.

[J-cat]

Sizing a mg fired case in a small base die is hard. A better approach is to size it in a regular Redding body die, then in a small base die. This two pronged approach reduces sizing effort because the regular body die sizes the case minimally. The small base version sizes the case a lot. This is both at the bottom and at the shoulder. You don’t want a stuck case or a broken press.