Grandson was shooting some reloaded 300 win mag and found several split/cracked in the end of the neck and one took the bottle neck off!! Any thoughts are apreciated.Some of the brass might be 40 years old and we got a case trimmer at Christmas.Checked powder several times?? Bud.
Just sounds like it's old to me. That and if it's been reloaded a few times without being annealed, wouldn't surprise me that it's doing that.
I shoot a 300 one of the best, kills from both ends a cyote don't have a chance at 400 yards. Throw away the brass. I found norma brass (virgin brass) lasted the best. trim for length after each shot, the gas tank behind that bullet is big , shoot sierra boat tail hollow points from memory they are 173 gr.