I've been using 45-70's on chucks since my early teens when I took the farm's Trapdoor out for a whirl. I like both of my BC's for chucks. one is in original chambering of 45-70, the other I rechambered after seeing Quick's to 45-120.
My furthest witnessed kill was over 550yrds with only 4 "walkers" on a 5-6" wide upright chuck. I'm surprised I hit'm because we were laughing so hard as he turn to look at the dust clouds getting closer.
My custom 300gr JHP's reamed out to 250gr, then tripped with a hotglue "spitzer" zing along at about 2200fps from my 22" Handi 45-70, 2500-2600fps from the 45-70 BC and about 3000fps from the 45-120. The thick jacket helps it stay together going down the barrel, but the soft homemade spitzer tip make is explode like a 45gr JHP from a 220 Swift X 10. lol