Case separation.

Discussion of BPCR loading techniques, SAFETY, Case Cleaning and Prep, Indexing, BP Choice, Primers, Wads, Compression, Drop Tubes, Vibration, Load Testing, etc.
Singleshot S.A.
PostsCOLON 95
JoinedCOLON Sun Aug 30, 2015 6:19 pm
LocationCOLON Adelaide. Sth Oz.

Case separation.

Post by Singleshot S.A. » Tue Jan 14, 2020 4:38 pm

Hi all,
I recently purchased some new Brass in 38/55 for re sizing to 32/40.
I have two rifles in this cal, and have resized many cases from 38/55.
I always anneal first, then take three steps to complete the sizing, and Don't usually loose many cases at all.
I then trim them roughly to length, fire form them, then trim them again.
This time I'm getting case separation. 2 out of 3 on the first firing. (Swiss 2f) So I unloaded all the remaining cases and re loaded with Wano P (no Swiss available here at the moment) only to have the same result again. I am loading a (full case) weighed 49.0 grns. With a LDPE wad for Breach seating.
Any thoughts. ?? I've never had this happen before. I'm using the same brass as always. They are separating at about 1/2 way down the case.
Should I re anneal them ??

I will go back to the old (Gaintwist) cases for now, but Don't understand what's happened.
By the way, the new Starline hold more powder than the Gaintwist, so wall thickness must be different. I also note that the Gaintwist heads are 2 - 4 thou thicker, surely that's not enough for a headspace problem in the Starline ??

If anyone has any Gaintwist cases they Don't need, I would gladly take them.