Quilly,
I use my 45-70 with the winchester factory 300 JHP. The recoil on it isn't bad at all, and that round will put any deer/black bear down hard out to 200 yds. And you can always buy the premium ammo when hunting larger animals.

If I were you, i'd either trade for a 45-70 or look at a pachmayer decelerator pad. The people on the Marlin Talk forum swear by them on their 450's and hot loaded 45-70's.