I recently encountered some case failures on W-W Super 22-250 rifle brass. The brass was new old stock, had been loaded for several years. 3 of the first 17 rounds fired has case failures. Some specifics
- The brass had the neck expanded prior to loading but had not been sized, it was new brass.
- The splits occurred in starting to mid loads and there was absolutely no indication of excessive pressure. I had fired the max loads during the round robin. The loads that split were relatively mild.
- 50 gr. Sierra Spitzer bullets, IMR 4350 Powder, Rem 9 1/2 primers
- Case weights were normal, nothing noticed as any different.
- I am sure the brass was purchased as a lot of 100 and the other 50 rounds had been fired previously with no problems.
I realize that in a brass case reacting to internal pressure, the circumferential stress is 2X the longitudinal stress. So it is twice as likely to split in a longitudinal direction rather than a circumferential. I just haven't seen case splits like this in new brass before near the case head. I have seen plenty of other type infant mortality failures in new brass (neck splits, etc.) Just thought I would share.
I intent to split the cases in the near future and check the interior. I pulled the bullets on the remaining 33 rounds and deprimed them. Everything looked normal. Powder was not deteriorated.