The only trouble with conicals in a 48" twist, is they are instantly unstable upon impact and do not travel in a straight line after impact.
This was proven on moose in BC. Due to the almost exclusive use of slugs in 48" twist rifles up to .54 calibre, the game branch got the
idea a muzzleloader could not kill a moose.
48" twist was ALWAYS a round ball twist & was used in virtually ALL Hawken rifles made in St. Louis.
That it would stabilize short slugs was blown out of proportion by TC with their button rifled barrels. All advertising hype to sell rifles.
Those guns did not have rifling suitable to patched round balls due to the shallow depth of it, ranging, actually measured by ME, from 1 1/2 thou. to 4 thou depth.
The rate of twist was too slow to stabilize a bullet after impact. They even turned up to 90 degrees on impact. Yeah- they're GREAT!