Headspace, Head Separation, Brass Life, Resizing, Kaboom

[FALPhil]

Gary's right. Those of us that reload and shoot a lot have all experienced case head separations in autoloaders. In fact, I posted a description of one on my first outing with my StG about 6 weeks ago. Autoloaders are very violent with the brass.

When I reload, I examine my cases for stretching, but sometimes one will slip through. Depending on the brass and the gun, I might get 10 - 20 loadings out of a case. Bolt gun brass tends to last longer because I only neck size. Autoloader brass, especially in military models, stretches more and gets full length resizing.

As a consequence, when I have the option of headspacing my own autoloaders, I tend headspace on the tight side, so my brass will last longer. The more the brass stretches and is resized, the quicker it work hardens, thins out, and splits.

Originally posted by gary.jeter:
A head separation is not an over-pressure incident or a kaboom (detonation).

I'm not advocating or condoning out-of-spec rifles or out-of-spec ammo. Over-resized handloads are the classic culprit. Still, a slight headspacing error probably won't create a dangerous situation.

[ July 22, 2001: Message edited by: gary.jeter ]

[W.E.G.]

To minimize the chances of head-separation (and preserve) your bottleneck rifle brass, you NEED a tool to measure the headspace dimension of your *brass. I have found the best tool for this job is the RCBS Precision Mic. You must buy a separate Precision Mic for each cartridge you reload. Price is $30 - $40.

This tool will allow you to precisely compare the dimensions of your reloads to factory loads, and if you choose to size your brass to a dimension other than the SAAMI spec, you will be able to measure the difference in thousandths of an inch.

When setting up your bottleneck rifle cartridge sizing die, the method of screwing the die down until it meets the shellholder, then backing off a half turn DOES NOT WORK! Ask me how I know.

Still, even with correct resizing technique, the bad news is that in a .308/7.62 autoloader, you cannot expect brass to reliably last more than three firings. The life of a brass case in a FAL (or an M1A or an M1) is short and traumatic. Even when your ammo fits the chamber of your rifle perfectly, a case will go about three firings before head separation becomes likely. At that point, many lots of brass will start coming apart at an unacceptable rate.

*Now, before somebody lights me up to extra-crispy on my comment suggseting that the term "headspace" can be applied to cartidge dimensions, let me say that I am well-familiar with that rant. Yes, I know "headspace" is literally the dimension between the cartridge case and the boltface. But, for the purpose of reloading ammo we must be allowed to discuss case dimensions in some language that makes sense (i.e. "headspace" of 7.62 NATO is 1.632"). Still, I do understand that, from a literal meaning, the headspace of a rifle of perfect dimensions, using ammo of perfect dimensions will always be ZERO.

Load and be ready...

[Wadman]

What is the problem or error with how the sizing die is supposed to be set up?