Shoulder Collapse...

[BCB]

Not sure where to post this, but since it concerns brass--here it is...

What is causing the shoulder to collapse when I am expanding the neck to 0.310" after it has been resized?...

This brass is R-P 30-40 Krag and has been annealed and probably reloaded at least 10 times...

Just case fatigue?...

Thanks...BCB

[Greg S]

Are the inside of the neck clean? You might need to swirl a qtip on the inside with some sizing wax/lube.

[EDG]

When you expand it with a mandrel from the mouth there is no support for the case body from your die. When a shoulder on the expander mandrel shoulder hits the case mouth the case will collapse since it is not as strong as the die. If you are using an M die make sure the top shoulder does not bottom out against the case mouth.

There are a number of things that might help

1. More lube on the expander
2. Less annealing of the shoulder
3. Expand with a .310 expander ball on the decapping rod pulling rather than pushing on the brass.

When a case fatigues it work hardens and cracks. That is why you anneal the brass.

[rancher1913]

when some did that on my 25-06 it was die adjustment. try backing your die away from the ram until it does not crush the brass anymore and then see if the neck size is still ok.

[Mk42gunner]

It sure looks like over annealing to me.