Lake City .308 Brass Sizing Issue

[Arrowshot]

I purchased some Lake City Match brass recently. All of them measure out to 1.980” on my caliper. Sounds kind of short when most say they should be trimmed to 2.005. So not real thrilled with the idea of firing in my Kimber to stretch it out if that is a good idea at all?

Some of it also had dents on the side and were significant enough that I discarded the brass. Is it likely the brass was shot in a MG?

 

[joshb]

I purchased some Lake City Match brass recently. All of them measure out to 1.980” on my caliper. Sounds kind of short when most say they should be trimmed to 2.005. So not real thrilled with the idea of firing in my Kimber to stretch it out if that is a good idea at all?

Some of it also had dents on the side and were significant enough that I discarded the brass. Is it likely the brass was shot in a MG?

Yup! That sounds likely. The good stuff is the “long range” brass shot out of bolt guns. I’ve never bought Match brass. How was it described? You won’t be “stretching it out”. Resize a piece and measure it again. Also, when you resize it, bump the shoulder back a little at a time until the bolt just closes on it. Write down that shoulder length, then push it back another 2 thou.

 

[Zero333]

25 thousands of an inch shorter than minimum "Recommended" length is OK to work with.

You won't have to trim for a while.

I am speculating when I say you may develop a carbon ring at the end of the chambers neck earlier than expected.

Of course it's not ideal, but only you can determine if those limited risks are worth it.

I've shot a handful of brass that I trimmed too short (1.990") with out any issues.

 

[dstoenner]

If this said match on the Head stamp it was not shot from a MG. The primers are not staked on match brass. My guess is that this brass was fired from a M14 and the dents are from the op-rod hitting the brass.

Did you measure the case length before or after you sized the brass. Most brass shrinks in length when fired and the process of sizing makes the brass grow back to length

David

 

[XTR]

...

I am speculating when I say you may develop a carbon ring at the end of the chambers neck earlier than expected.

....

I would not worry about this.

I used to worry about trimming until one day I looked at the SAAMI spec measurement to the end of the neck in the reamer prints, in case you've never looked it's 2.025 to 2.040, so trimming to 2.005 gives you .020 clearance. The spec on the brass is 2.015, so the whole trim to 2.005 is actually pretty short.

Based on the cultural agreed upon 2.005 trim I don't think the extra clearance is going to matter.

 

[Zero333]

I would not worry about this.

I used to worry about trimming until one day I looked at the SAAMI spec measurement to the end of the neck in the reamer prints, in case you've never looked it's 2.025 to 2.040, so trimming to 2.005 gives you .020 clearance. The spec on the brass is 2.015, so the whole trim to 2.005 is actually pretty short.

Based on the cultural agreed upon 2.005 trim I don't think the extra clearance is going to matter.

I measured the chamber's in my 308 barrels and they end around 2.035" ( if I remember correctly... To lazy to check again).

So I let them grow to 2.025_-2.030" before trimming.

 

[JFrank]

I purchased some Lake City Match brass recently. All of them measure out to 1.980” on my caliper. Sounds kind of short when most say they should be trimmed to 2.005. So not real thrilled with the idea of firing in my Kimber to stretch it out if that is a good idea at all?

Some of it also had dents on the side and were significant enough that I discarded the brass. Is it likely the brass was shot in a MG?

I bought brand new 308 Nosler Brass more than once that measured 1.995
That stuff cost $1.00 a piece plus tax !
Nice Brass BTW
Anyway they shot just fine and at about 5 X re loading them I finally trimmed them to 2.010

 

[msinc]

Not all LC match brass has "NM" or "Match" written on the bottom. A lot of it does, but there was some that had a weird knurl around the case just above the case head right about where a case will separate when it fails. That knurl signified Match ammo. They also had stuff called "Mexican match" which if I am remembering right was ball ammo that had the FMJ bullet pulled and a BTHP bullet seated. That was many moons ago, but there still could be some floating around.
I have messed with military brass and specifically LC brass all my shooting life and I have spent considerable time trying to find a discernible difference {other than possible markings}. I have not. I have a lot of LR currently and I resize it and use it for 243, 260 and 7mm-08. It works great, but not any better than LC58 {for example}. My personal experience...don't pay extra for "special" cases and if you can get any LC at all, just get it and shoot it.

 

[granite1]

“Mexican match” is slang for when a shooter pulls bullets from “ball”ammo and replaces them with better. LC didn’t do it. The nice thing about “match” brass is the primers aren’t crimped. Some of the “LR” brass was weight segregated by “LC”, but I couldn’t tell ya the years they did it. I wouldn’t worry if yours is a little short.