Do I have a chamber problem?

[303Guy]

Do ppl find the no4 is hard on brass? everyone I talk to thinks so....P14 on the other hand is far kinder....

I seem to be the odd man out - I have serviceable brass over 30 years old. It neither stretches nor cracks. Neither does it expand at the web like that. The only case losses I've had over the years is to long grass. I never need to set the shoulders back either. I should hasten to add I do not load and fire them every day but some individual cases get used for load testing and those get loaded several times a day when I'm doing that.

Annealing often is a requirement for consistent neck tension so should be done after every three or four firings.

I've never seen an undersized case so I can't comment on that. Those cases may be thin wall so the very marked expansion ring could be explained but it looks like high pressure. The primer needs to be examined. It's not the outer primer radius so much as the firing pin indent radius. A primer that shows the outer radius is fine but one that is flattened only means it might have backed out and was reseated on firing.

My cases don't normally show such a dramatic expansion. I do have some very old cartridges and they show their age with tarnishing. One doesn't often see annealing stains on commercial brass - they get polished. Military brass doesn't. Apparently the military requires annealing stain because of the problem un-annealed brass can cause. PRVI brass comes with annealing stain.

Where the brass comes from when cases stretch is the web area where it weakens the case leading to case head separation.

I had some reformed military brass in 25-303, some of which were cracked with age. Those that weren't were pulled and annealed then reloaded with no problem. Those that were not pulled all split on firing. So it seems that if the cases can be annealed in time they are fine. (The factory that did the reforming did not reuse the cordite).