I have an 1895 gs in 45/70. With 300 grain softnose bullets loaded to about 1500fps, I can shoot a box of 20 fairly easy without getting too sore. With 400s loaded to like 1700fps after about 10 I dont want to shoot any more. I am going to load some bear loads with 500's that will surely tear my arm off.

If you can shoot 180s out of a 30-06 youcan shoot the 300 fairly easy. The 06 actually has a sharper kick. The 45-70 has a very hard push.