burntwater wrote on Aug 9
th, 2026 at 1:49pm:
Anybody know the reasoning for why bottleneck cases should be problematic or was this just idle chatter ?
Rick
OK, I'll be the fly in the ointment. When I started working on loads for my original 44S Rolling block I had all sorts of cartridges. I wanted about 100 ready to use for the 2024 Creedmoor match in Tenn. I had some re-worked .348 cases, JBA 44-77, JBA 43 Spanish, Bertram 44-77, Berdan primed 43 Russian and some original Remington UMC balloon head brass, a real mishmash. 82 gr Swiss FFg was the load I settled on. While practicing, the re-worked .348 brass were the first to pull apart. (I had previously used these and much of the others in a 44-77 Smokeless Rolling Block I built, using smokeless with no problems). I thought maybe the web had been weakened when the brass was turned to fit the chamber - by the previous owner. All of those went away. Ultimately, the only group that had no pull apart failures were the original UMC cartridges. I did lose a couple to neck splits, however.
The .43 Russians were interesting. The rim is a two-piece rim and a few of those had rim separations.
All the brass had been annealed before fire forming to the "new" chamber and all the brass had been fired at least once prior to an occurrence.
I posed the question of why does this happen to a world class BP shooter. His working theory is that Swiss FFg is a harder granule than most and when those hard granules start to move they hit the neck and stretch the cartridge. In his experience, a load of 95 grains of Swiss FFg would tear about 50% of the cases. My guess is that the UMC cases didn't tear because they were made for an original rifle or the balloon head gave room for the gases to expand a bit before they hit the neck. The other brass took the full brunt of a harder powder right to the neck. -- I don't know for sure--
I am working on a different load. I don't know how to determine if a powder is "soft" or "hard".
Anyway, that's my story.
-06