Hook686
US Veteran
Interesting! I've never had that happen with any of my reloads. What kind of crimp are you using? I have a Lee Factory Crimp die in the last station on my Dillon 550. I put on a pretty healthy crimp because I've been loading for .357 lever guns.
I also use the Lee Factory Crimp Die. I put a tight roll crimp on each cartridge ... any tighter and the case buckles a bit. I must say that I have only experienced this in the 6th shot of my 686, but have experienced it in the 3rd shot in my M&P 340 using 6.8 grains of Unique.
I use MagTech 158 SJSP bullets.