I dont have first hand experience, but the guys on the leverguns forum that have shot game, up to moose, with them seem to like them. Seems like with decent powered handloads they were getting complete pass-throughs on large animals.
The old Lyman manuals showed loads with 250 gr bullets at 1800 fps vel as intended for Wincheter 94's.
I'm building a 94 in 38-55. Hoping to try it on various critters eventually. A neighbor that's used 38-55s said they were noticably better than 30-30 loads on game.
"Far better it is to dare mighty things, to win glorious triumphs even though checkered by failure, than to rank with those poor spirits who neither enjoy nor suffer much because they live in the gray twilight that knows neither victory nor defeat." -Theodore Roosevelt-