I'm using .44 Rem Mag dies from Redding for my 445 SM. I use a decaping die first for primer removal then resize about 3/16" of the case with sizer die, only because the decaping rod set this way will not punch out the primer. I'm shooting a .431" hardcast bullet in Starline brass and even on fired cases you can't slide a bullet in, so the little bit of sizing and a good heavy crimp does quite well. You could spend the extra $100-$125 dollars and wait time for a 445 SM set to be made, but you should be fine with several of the 44 Rem Mag dies out there. I've just been getting started in the 445 SM realm and find it to be a very accurate and nice shooting cartridge. Good luck and enjoy.