I agree. Not overloaded. That load is similar to what I used in silhouette shooting for several years. Some of the earlier Remington brass would split. Once you culled out the bad ones, the rest worked pretty good.
For use in my contender, I only sized the brass to get the bullet to seat. I did not do a full length size. If you full length size, look at the brass closely and measure it. You will see what is called a 'coke bottle effect'. Kinda slimmer in the middle. Work harden this area, get the cracking you describe.
So, once fireformed in your contender, use a carbide sizing die and size about the 1/4 to 3/8" of the neck and call it good. I also seat my bullets in one step, then use profile crimp die after bullet seated.
No more brass problems.
Steve
P.S. I have experience with the 357 max in Ruger, Dan Wesson, and T/C.