68coupe asked about crimping the 30 Mauser when reloading. It was an old thread so I created a new one to respond.
I have the Lee 3-die set and the seating die has a crimp option. The instructions point out that if crimping you need to also trim the cases so that the crimp is uniform.
So it is an option but does not seem to be required. I crimped my boxer primed spent cases, but most of the time I was pulling bullets from Tokarev ammo and then reloading with some lower power Reddot charge, and in those cases I did not crimp. I never had any issues with either load.
Cheers!