One facet of this discussion that doesn't get talked about quite as much as I'd like to see is the relative strength of 45-70 brass vs. 450 brass. I stay well within published data for 45-70 in the 1895 Marlin, and I find myself having to check my brass regularly with a paper clip. I don't get a LOT of incipient head separations - just enough to make the check mandatory. - Kind of like hotrodding 30-30 for a contender.
I've always suspected this is one of the problems the 450 was designed to address. Again, this is only my speculation. SW
