I've shot alot of lead through a 7 1/2" SRH 480, so am quite familiar with what it can do in a handgun. I assume that a rifle will gain an honest 300 fps over the revolver. Using that as a basis, handloads will drive 325 gr bullets 1700-1800 fps, and 400 gr bullets 1500 fps. That means it basically falls 200-300 fps shy of a 45-70. Not to shabby considering it burns less then 1/2 the power a 45-70 does.
It's my hands down favorite revolver, and I'd love to have a companion lever gun.