LC 13 GI brass

[jaysouth]

Last winter I bought several hundred cases from my local enabler. Over time I have gotten around to full length resizing them, de-capping, chemical cleaning, tumbling and reaming out the primer pocket swage.

I was loading some this week and decided to check the case length. These are Lake City cases that I am sure were fired in some variant of the M-240 Machine gun. To size them with as little effort as possible, I soaked them in 2 cycle engine oil and mounted the Rock Chucker on a bench outside. It was messy but easier than using sprays or sizing wax. I had to use a pressure washer to get all the oil off the press, resizing die and bench.

Case lengths ranged from 2.008 to 2.041. I trimmed all of them to 2.008-2.009 with my new Lee crank handle trimmer (SAAMI standard is 2.015).

How could the OAL have such a range for once fired brass? Do different lots of brass flow/grow different from other lots?

Looking back on this project, if my time was worth minimum wage, it would have been cheaper to buy Lapua virgin brass.

(by the way, Lapua brass is selling at Midway $72.95 per hundred, which is cheaper than the Hornady match brass listed for sale there.)

[winelover]

Last winter I bought several hundred cases from my local enabler. Over time I have gotten around to full length resizing them, de-capping, chemical cleaning, tumbling and reaming out the primer pocket swage.

I was loading some this week and decided to check the case length. These are Lake City cases that I am sure were fired in some variant of the M-240 Machine gun. To size them with as little effort as possible, I soaked them in 2 cycle engine oil and mounted the Rock Chucker on a bench outside. It was messy but easier than using sprays or sizing wax. I had to use a pressure washer to get all the oil off the press, resizing die and bench.

Case lengths ranged from 2.008 to 2.041. I trimmed all of them to 2.008-2.009 with my new Lee crank handle trimmer (SAAMI standard is 2.015).

How could the OAL have such a range for once fired brass? Do different lots of brass flow/grow different from other lots?

Looking back on this project, if my time was worth minimum wage, it would have been cheaper to buy Lapua virgin brass.

(by the way, Lapua brass is selling at Midway $72.95 per hundred, which is cheaper than the Hornady match brass listed for sale there.)


Reloading must be viewed as a "Labor of Love"-----I, for one, just plain enjoy it.

Brass will always have variances. A result of different manufactures, lots, etc. Military brass, usually, is fired in different guns, with different chamber dimensions. Standard procedure, should be uniforming your brass. That includes trimming, after sizing, close to minimum dimensions. The 2.008" / 2.009" is what I try to maintain for 308W brass.

You will save a lot of time and headaches, with a power trimmer. If you dislike trimming, as I do. Invest in RCBS X Dies. They pretty much keep the brass from growing with subsequent sizing. In other words, size once and forget it.

I bought some LC military brass from a member of this forum. Good brass. Machine gun fired. I had no trouble sizing on a RCBS JR press, with little effort. I used Hornady "Unique" case lube and the aforementioned X-dies.

Winelover

[Scharfschuetze]

Most of the 7.62 brass now on the surplus market, is as you surmise, fired from full auto weapons. M24 and M40 brass is like any once fired brass and is your best option, but how do your know? That's the question. Who knows what you're getting from the dealer. He probably doesn't know either as base DOL (Department of Logistics) just sells the brass after it is turned in at the base ASP (Ammunition Supply Point) and just lumps it all together once it is checked for live rounds.

I wouldn't worry too much about your case length as that can be fixed easily as you've done. What I would worry about with GI brass following full auto use is the web. Full auto weapons can be pretty violent in their ejection and the case web can get stretched and be a few loads away from an incipient separation.

The X Die suggestion above is a good one.

[MtGun44]

If the gun had a lot of headspace, the case will stretch to fill it. This is where your
long cases come from. Those cases will have shorter life than the ones that are
at 2.008 when you got them because they are already stretched a lot.

For educational purposes, take a 2.008 case and a 2.041 case and saw in half. You
will see a ring inside the long case where the stretch occurred - it all happens in
a small area about 20% of case length from the case head forward.

Bill

[Love Life]

LC LR is fired in the M40 rifle series. That is the good stuff.

[Scharfschuetze]

LC LR is fired in the M40 rifle series. That is the good stuff.

Yep. In years past it was White Box M118 Match and later in the 90s and early 2000s it was M852 Match. Both of those were/are easily identifiable as they say "LC XX Match" on the headstamp without any crimp on the primer and were at worst case fired through M14 NM or M21 rifles and best case through M24 or M40 rifles.

M118 Special Ball also used in the M24 and M14 NM rifles post 1985 or so used ball cases with crimped in primers and is thus indistinguishable from M62 or M80 ball.