Lake City 5.56 brass length

rebs · November 4, 2018, 11:34 AM

Why are some Lake City once fired brass so long from just being fired one time ? Some are shorter.

Reloadron · November 4, 2018, 12:23 PM

Once fired brass could have been fired in any number of different guns. For example a M249 light machine gun commonly called a SAW (Squad Automatic Weapon) which might have a longer chamber than for example a M4 Carbine rifle.

I have found the same to be true of 7.62 NATO once fired in a M60 Machine Gun.

All depends on what it was once fired in.

Ron

Brian Pfleuger · November 4, 2018, 12:23 PM

Brass length is determined by many factors, including the tooling that made the cases. LC has many such machines, I’m sure. Also, if fired in different guns chamber dimensions will influence. Different peak pressures and durations will/may have an effect as well.
I use a lot of “premium” Norma brass. It also varies after first firing.
It’s just one of those things that “is”.

F. Guffey · November 4, 2018, 12:58 PM

Quote:

Why are some Lake City once fired brass so long from just being fired one time ? Some are shorter.

I DO NOT KNOW and no one else knows because they do not know if you are measuring the length of the case after firing or after sizing. I am the one that is not concerned with the length of the case; I am the one that is interested in the length of the case from the datum/shoulder to the case head. I want my necks to get shorter and my case bodies to get longer from the shoulder to the case head.

Again: I have had cases shorten from the end of the neck to the case head .035" without the case stretching between the case head and case body. All of shortening

was measured after forming, sizing and firing and then sizing again. And I have had cases shorten as much as .045" with some extreme wildcats.

Spme where in all of this sizing, firing and sizing the reloader should be able to determine if the case stretched and where it stretched. And then there are a few reloaders that are fans of reducing all that case travel if that is what the cases does and or did.

F. Guffey

T. O'Heir · November 4, 2018, 02:04 PM

Like Reloadron says, Lake City, once fired, brass, assuming it's milsurp, can have been fired out of MG's or M-16's or M-4's. All of 'em, like every rifle, have different chambers.
Brass being different lengths after firing is perfectly normal. S'why you must check the lengths before reloading.

November 4, 2018, 11:34 AM	#1
rebs Senior Member Join Date: January 10, 2012 Posts: 3,881	Lake City 5.56 brass length Why are some Lake City once fired brass so long from just being fired one time ? Some are shorter.

November 4, 2018, 12:23 PM	#3
Brian Pfleuger Moderator Emeritus Join Date: June 25, 2008 Location: Austin, CO Posts: 19,578	Brass length is determined by many factors, including the tooling that made the cases. LC has many such machines, I’m sure. Also, if fired in different guns chamber dimensions will influence. Different peak pressures and durations will/may have an effect as well. I use a lot of “premium” Norma brass. It also varies after first firing. It’s just one of those things that “is”. __________________ Nobody plans to screw up their lives... ...they just don't plan not to. -Andy Stanley

November 4, 2018, 02:04 PM	#5
T. O'Heir Senior Member Join Date: February 13, 2002 Location: Canada Posts: 12,453	Like Reloadron says, Lake City, once fired, brass, assuming it's milsurp, can have been fired out of MG's or M-16's or M-4's. All of 'em, like every rifle, have different chambers. Brass being different lengths after firing is perfectly normal. S'why you must check the lengths before reloading. __________________ Spelling and grammar count!

November 4, 2018, 12:23 PM	#2
Reloadron Senior Member Join Date: June 8, 2016 Location: Cleveland, Ohio Suburbs Posts: 1,750	Once fired brass could have been fired in any number of different guns. For example a *M249 light machine gun* commonly called a SAW (Squad Automatic Weapon) which might have a longer chamber than for example a *M4 Carbine rifle*. I have found the same to be true of 7.62 NATO once fired in a M60 Machine Gun. All depends on what it was once fired in. Ron