OK, that is still a different type of factory crimper. The one LEE sells for 454 casull is not the open topped version. It is one like you would get for 44 mag. It puts a roll crimp instead of the circular pinch type that the 45-70 gets. Or am I totally confused about the operation of this Lee FC die?
I checked with Hornady. The 450 Bushmaster uses a different type of bullet. I was told in addition of the crimping groove the base is thicker and it has the flex tip. And no,... It will not be offered as a component as of yet. Shucks! I asked a bit about the jacket on the SST ML, and they said it is not a thick jacket, but I think muzzle-loader speeds and 454 cas speeds should be close. The pressure is what is concerning me, at this point. Now there is a big difference. If I decide to go forward it will be with XMP-5744, to get some lower pressures. What good is a separated jacket?