hi MDman,,you know i have been doing the BPCG game for a lot of years now,,and these guys have given you some really good info.
for me i like the 45-70,,,it has done for me everything i have ask it to do and not beat me up to bad doing it
in the last few years there has been a swing in the long range crowd to the 45-90......i will say this if you decide on one of these longer cases,,,DO NOT USE A SHORTER CASE IN THE CHAMBER,,,, if you ring the chamber you have recked the chamber,,, when you go back to the original cartridge it will expand into the ring and extraction will be a pain in the the arse
those long cartridges will get a lot of ooooh's and ahhhhh's for style points,,,and i don't know to many people that can make them work,, there are a few,,,,but they are living with the gun to unmask the secrets of the big boomer,,,, and they will KICK the hell out of you
my recommendation if you think you want more than a 45-70 would be a 45-90,, use 45-90 brass and load it down,,,, i will say that a full house 45-90 loads will start to be painful at the end of the day,,, i use black powder in my 45-70's,,, i can load 75 grains of 2f under a 535 gr. tapered bullet that i cast,,, the beauty of the tapered bullet is only half the driving bands are in the case the other half is in the bore,, so like has been said i can get more powder in the case.... i also use some of my guns to hunt with,,,i like a 480gr. NEI gas check lead bullet over 71gr of 2f,,,, that load will put that bullet through an elk at 225yrds.,,,,it has also taken 2 buffalo,,,along with several deer,,,,, i don't know how one of the bigger cartridges could do it better
i think there are some 45-90 smokeless loads out there but not very many,,, from there on up it's black powder
i don't mean to step on anyone's toes,,, this is just my experience through 25 years with black powder.....YMMV
ocharry