Need advice re: M1 Carbine brass

[rdwarrior]

I am awaiting arrival of my first M1 carbine. I had an individual donate some brass to me for reloading. I was told it was sized and trimmed to proper length. Well I went through each piece today checking length. Majority of the brass was trimmed to 1.260 - 1.269. About another third was trimmed 1.270 - 1.277 and 30 pieces were trimmed to 1.278 - 1.285. Since this round head spaces on the case mouth and should be trimmed to 1.280, is it safe to assume that all the brass shorter than 1.277 is basically trash and should be thrown out? If i resize each piece again, will any of it stretch out to 1.280?
TIA
rdwarrior

[ShooterAZ]

Yes, try re-sizing some of the shortest ones and see what that does to them. That does stretch them. I'd go ahead and load the 1.269 brass, my Aguila brass started out somewhere right around that length.Then get your trimmer set up, because you'll be needing it soon.

[Texas by God]

I would say that it depends on your M1 carbine. I've loaded for mine for 2 years now with jacketed and cast bullets and I have never measured a single case. I have also used mixed had stamps.

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[Winger Ed.]

I'd load & shoot it.

Looking at brass where I've fired just a primed case, the primer always backs out part way.
I figure that is some sort of tolerance built into things.
If the case is a little too short, and goes in deeper than say a once fired case would, the firing pin can still reach it.

[Der Gebirgsjager]

I'm with them! I've never trimmed my carbine brass, and it all works fine. Just like 9mm or .45 -- never trim them either.

[ShooterAZ]

I trim new Carbine brass to get them all to a uniform length. After that I check them periodically, and have found some that needed to be trimmed again. The tapered case "squishes" longer in the sizing process... that's been my experience anyway. YMMV.

[psweigle]

Carbine brass does stretch. Size the shorter cases again and recheck.

[jimb16]

Since the carbine round uses a tapered case, shorter rounds can usually be used safely. The taper will prevent the case from going in too deep. I rarely need to trim cases.

[rondog]

Choot 'em!

[bob208]

give them a try. I too have not trimmed or measured when loading for the carbine. I do have a ruger Blackhawk that likes short brass.

[georgerkahn]

Having been an M1 Carbine loader for quite some time, the "rule" *I* adhere to re case length is:
~~~~~~~~~~~~~~~~~~~~~~~~~~
30 Carbine Case Length (after sizing):
1) 1.286" and under: UNreliable
2) Between 1.287" and 1.292": OK
3) 1.293" and over: May jam action
~~~~~~~~~~~~~~~~~~~~~~~~~~
I've never appreciably noted stretch in case lengths -- for me, the brass getting work-hardened being more of an issue. (Note: I only have/use military brass) I've annealed quite a few, but cannot testify this as a cure-all. Not to (hopefully) start an off-topic discussion, but I frankly feel the alloy used to form WWII/Korea military brass was not made with subsequent reloads in mind ;).
One of my major criteria is that all cases be of similar length -- one which functions in your firearm -- and, with moderate loading, I'd suggest your cases will split at neck, etc., before they stretch. At least, this has been my experience.
BEST wishes with your carbine when it comes!
geo

[MostlyLeverGuns]

The M1 carbine ejector will 'seat' the round and hold it against the chamber lip (headspacing on the front edge of case neck). This keeps the cartridge from moving so the firing pin can hit the cartridge without losing power by moving the cartridge forward. As long as the firing pin can reach the primer (within reason) the cartridge will fire. Case length is not critical. Such plunger ejectors do help in some ways toward reliable ignition in many firearms, Winchester lever actions, Remington 700, AR15, many other bolt, auto and other guns - the cartridge is pushed and held solid in the chamber by the ejector, so there is no cartridge movement when the firing pin hits the primer. Consistent length is usually more important for accuracy AND reloading the case.