short brass life in my M1A


May 29, 2003, 09:33 PM
Im looking to get a little more out of my M1A brass. I get head seps after 2 firings. I use a mild load, (40.5 grn IMR4895 under a 168 SMK, in LC cases). I have heard a couple completely different solutions- #1-Sniper`s Hide: Only size case enough so bolt closes completely when tilted on a 30 degree angle, muzzle down. (with firing pin, extractor/ejector, and op-spring removed) #2- Zediker: use case guage and size to its dimentions and possibly use small base dies. I have a custom built M1A with a fitted Douglas heavy barrel. I doubt the chamber is cut wrong. (Very reputable `smith) What do you guys suggest/ your thoughts? Thanks-

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Steve Smith
May 29, 2003, 11:18 PM
I say use a case gauge on a fired case and bump that shoulder back .003" max. Try it and see.

May 29, 2003, 11:26 PM
#2- Zediker: use case guage and size to its dimentions and possibly use small base dies.

Personally, I would not load for a gas gun without a case headspace gauge. I prefer the micrometer type as made by RCBS. Measure 8-10 once fired cases and set your die to reduce the average headspace on those cases .003" shorter than they came out of the rifle. This will assure your cases will fully chamber without over working the brass. Over working your brass is what causes premature case head separation in most instances.

One word of caution regarding headspace on gas guns. The garand and the M1a both have floating firing pins that "peck" the primer pretty hard as the bolt slams home. It is recommended that you run your cartridges through the magazine/clip in order to let the friction of stripping the round out of the mag/clip slow bolt. Also avoid soft primers and be sure they are seated fully. Headspace is critical also as chambering a round that is too large can result in slam fire.

I have reloaded a number of years for three different M1's and two different M1A's (one M1 and one M1A had snug match chambers) and never found the need for a small base die. If you were using surplus brass which had been fired in a machinegun and your rifle has a match chamber, you might have to use SB die the first time to bring the cases down sufficiently to chamber but cases worked this much will not have case life of brass fired in rifles only. Machineguns have pretty sloppy chambers resulting in oversized brass, but once it is brought back to specs you should not need SB die again.

One other thing you should take into account is that brass work hardens as it is fired/sized. A die set to bring a once fired case down to .003" smaller than it came out of the chamber will not bring a case fired and reloaded 6-7 times down that small as the harder brass springs back somewhat after sizing.It is therefore important to check the sized cases in your case gauge each time it is reloaded to insure against slam fires.


May 30, 2003, 03:42 AM
I'm on my 7th reload of LC 93 and 68 brass. This stuff is exclusively loaded with and a fairly stout load that throws a 178 AMAX at 2625fps from my M1A (with an Accuracy Speaks vented gas cylinder plug to bleed off the excess port gases and eliminate bending the op rod).

I haven't had a head separate yet. I think the secret is the RCBS X-die I use to resize the brass. First, I trim all my cases according to RCBS directions which specify .005" under minimum trim-to-length, which makes it 1.995" as the starting case length. After 5 firings, the cases stopped shrinking at ~2.007-2.008". I check the inside of each case before reloading for indications of head separation, but so far, it hasn't surfaced. My cases used to show separation tendencies between the 2nd - 4th firings with regular sizing dies. I set the X-die to bump the cases by .003" also. Make sure to deactivate the gas plug in order to maintain a true case headspace sample. You don't want the ejection process to stretch your cases and distort the headspace measurement.

To alleviate the possibility of doubling or slamfiring, I use a primer pocket uniformer instead of the pocket cleaning brush, and ream the pockets square and ~.007" deep. As I recall, Zediker suggests .004-.011" as an acceptable depth. I haven't ever had a double since I've begun the uniforming regimen (~2000 rounds).

May 30, 2003, 07:51 AM
Other than expense, is there a reason to use military brass instead of commercial 308 Win brass?

Steve Smith
May 30, 2003, 09:26 AM
Not really. They're good cases, though.

May 30, 2003, 10:23 AM
BigG, Zediker and others say that mil brass is harder and thicker than commercial brass. In the M1A and Garand, this is desirable, due to thier almost "violent" exraction. In most peoples rifles that would probably mean more loads before you toss `em. In my rifle, it seems it really wouldnt matter! :banghead:

May 30, 2003, 11:07 AM
Yeah, I think it's harder because it has to function thru MGs. Nothing like an M60 or a minigun to tear up some soft brass.

August 27, 2005, 03:02 AM
Does the M-1a eject brass straight up? How does this affect scopes?

August 27, 2005, 03:09 AM
You've got to be waaaaaaay oversizing if you're seeing separations at 2 reloads (or you have a bad batch of brass).

Get a gage. Shoot some factory ammo and measure it. If you use cases you've already sized in your die, you'll very likely get erroneous results. Set your sizing die to bump it back by 0.002-0.004".

If you don't have a case gage, you are simply guessing (even by following the die manufacturer's instructions). It wouldn't surprise a bit me if you were pushing the shoulder back by more than 0.010".

I wouldn't bother with small base dies unless you cannot get reloads to chamber.

August 27, 2005, 03:13 AM
A lot of the once fired military .308 Win brass like the LaKe City sold has been shot through machine guns like the M60 and can be/are stretched pretty good as a result. When using that brass for reloading you will likely get less reloads out of them.

August 27, 2005, 08:26 AM
Your gun may have a headspace problem. Brownells sells a set of headspace gauges (10) in .001 increments for the M1A so you can see exactly where you are with this rifle. If you are stretching your brass on the first fireing because of headspace you will only get a couple of loads out of it before you get a case seperation, even if you neck size only after that! Look for the bright ring near the head after the first fireing and section the brass if there is any doubt.

August 27, 2005, 10:25 AM
What kind of brass is suspect? Are you using milsurp? (there's no telling if that stuff is machine-gun-fired or not, and that'll shorten case life to one or two reloads for sure) If so, I'd try loading some store-bought new brass; even Federal will do. They have a rep for softness and the primer pockets supposedly stretch by the 3-4th firing so that the primers fall out, but that hasn't been my experience. (Also, *new* milsurp brass has lasted me 7 reloads w/ an X-die)

Steve's suggestion of bumping them back only .003" is good too, but I'd add that no round gets loaded in my M1A mags that ain't measured with a Wilson headspace guage.

I don't think small-based dies are a necessity, unless the chamber is tighter than you suspect. The small-based dies will contribute to more than the routine stretching caused by normal dies.

August 27, 2005, 04:03 PM
Already answered, post deeted

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