Brass bulge

[Kurt]

I have that problem with my Browning .40-65 and I even had the cases separate about a 1/4" ahead of the rim. I think it has to do with the generous chamber the Browning has and the .499" diameter of the head on the Starline cases. After a few shots fired the case expands to match the chamber wall and the case gets thin at that point and eventually separation occurs.
I sent several cases to Starline with this problem but never got a reply from them.
I think this might start when they run their draw die through the case stretching a weak spot. ????