30 carbine case bulge

How much is too much? I am new to loading this cartridge, using my own factory loads, over 1000 rounds so far, up to three times fired, and there is no bulge in fired brass.. Bought some brass-in-a-baggie today, on inspection the cases were over by 2-3 thou. 1/4 inch forward of the case head. It was visually apparent. So I bought some junk brass. Other baggie purchases had loose primer pockets or were too short when sized, but this was my first batch of potbelly brass. I assume that any bulge is NG. What say ye of greater knowledge?

.002-.003" increase in diameter forward of the solid head is totally inconsequential. Simply a product of normal and necessary clearance between case and chamber. Even .010" would be within SAAMI tolerances.

Considering that reloading "in the field" was / is not widely practiced in ANY army of my acquaintance, it is not a problem.

It's only when normal folks on limited budgets get involved does "brass life" become an issue.

LOTS of Lee Enfields "bulge" their brass on firing. It almost NEVER ruptures and it seems to have no effect on extraction and ejection.

"Cleaning out" of chambers is also common in the "surplus trade". Most of these operations are not too worried about a bit of "extra"' chamber clearance; it makes the firearm look better to the buyer and (generally) ensures reliable extraction from an otherwise "shabby" chamber. EXCESSIVE "scrubbing" of a chamber will cause it to become "oversized", but usually not to the dangerous mark; it just "over-works" your brass.

As a general guide, if you are using commercial brass and are reloading, the neck MUST be sized correctly and the shoulder "bumped". This will require the suitably-named "neck-sizing" die. Only use the FLS die to resize the body of the case just enough so that it will neatly re-enter the chamber in which it was fired.

It is all a bit of a fiddle; but these things are governed by the state of your wallet and the extent of your patience.

I fully size all of my brass for most applications. That way it is "one size fits all" of the same calibre, as per the original military idea. Regular annealing will ensure a longer life for the case. Regular TRIMMING to correct length will ensure a longer life for the rifle and firer.

Your .30 Carbine cases, being pretty much dead straight, headspace on the case MOUTH, there being no rim, shoulder or "belt". That is why overall length is important; too long and they will either not chamber, or, if they do, the crushing of the neck into the bullet will cause chamber pressures to rise dangerously.

Too short a case will result in erratic or NO ignition of the primer.

Find a shooting buddy who is a precision reloading enthusiast and get some "press time". Ultimately, pulling the handle on a good reloading press will be cheaper and more satisfying than pulling handles in Vegas, (mostly pushing buttons these days, anyway).

I agree with the statement that once sized the bump, or bulge will be gone. Forget it and size them full length. Shoot it until the brass cracks and discard it. Simple.

Any bulge less than .006" is going to be ok. .006 to .008 is not so hot. .008 to .010 will shorten the life of your brass. More than .010 is really asking for trouble.

I have a few brass and chamber combinations that range from .002 to .003 bulge. It is formed to a .000 clearance at the shoulder. When used with ordinary loads the brass will last 30 to 50 reloads assuming you anneal it now and then. There are no splits and no case head separations. The primer pockets just get loose from having so many primers pressed in.

Thanks for the intel. Happy camper here. Didn't know one could get so many reloads out of 30 carbine. Don't need to buy any more strange baggies, or even touch my precious stash of unfired LC, which doesn't seem to be available anymore. I just hadn't encountered any bulge in brass that has only been fired in my carbines.

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Originally Posted by gatorwade

Don't need to buy any more strange baggies, or even touch my precious stash of unfired LC, which doesn't seem to be available anymore.

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I'm finding that some of the early LC (43) is getting a little too old for reloading. I fired a couple boxes last time I went shooting and about 30% of the cases were found to be split. It's probably time to shoot it, or sell to a collector. - Bob

The old LC will go with my carbines when I pass on. But for the moment they will serve as a security blanket for the inevitable, next, ammo panic. Or call to duty the day when it is time to load all the magazines. It was accurate ammo, but I did get a few splits. Haven't shot anything but reloads for the last couple of years. So much empty brass, so little time.