Case Head Separation?

[GLOOB]

I think I'll give a go at backing out the die until the cases barely fit to the long end of the gauge, next time.

Are you shooting bolt, or gas gun?

Gas gun. But as long as the brass fits the max length of the chamber gauge, I figure it should be ok? There's a range of length on the Wilson case gauge, so I assume that anything in that range should be within spec?

 

[TonyAngel]

I don't agree that dies can't cause an excessive headspace issue by bumping the shoulder back too far. Back when I first started reloading bottleneck cartridges, I started with a set of Lee dies. I set them up as per the instructions. On my third reload some of my cases starting showing the tell tale signs of separation. I got a case gauge and found that setting the dies up according to the instructions have me bumping the shoulder back way too much. I now set up my dies using a case gauge.

I use a fired case to get a measurement and then set the die to bump the shoulder back a few thousandths.

Anyway, you have to watch out for that 5.56 brass. I don't know where you got it from, but I got some a while back and found that some of it must have been fired out of a SAW or something because they were expanded way beyond what they should have been and were more difficult to resize. This is just the conclusion that I came to after having a couple of separations with that batch of brass.

 

[dmazur]

But as long as the brass fits the max length of the chamber gauge, I figure it should be ok? There's a range of length on the Wilson case gauge, so I assume that anything in that range should be within spec?

I reload for a Garand (which is another gas gun) and the general guidelines from many who reload for gas rifles are to treat them differently. Perhaps 0.004" to 0.006" less than fired length (which might be the same as chamber length) but not the 0.001" or 0.002" customary for a bolt-action.

Chambering without interfering with the bolt's ability to rotate to the closed position is more important than brass life, in other words.

The idea is to find a happy medium between increasing the risk of slamfires and increasing the likelihood of case head separation.