I watched a shot taken (I was about 300yards from them at that time, gutting another moose) of a client and his guide shooting at a moose, 170 yard shot by laser range finder.
The rifle was a .54 TC - had a cut rifled barrel seems to me, & was loaded with a .018" pre-lubed Oxyoke patch + a swaged Speer or Hornady .535" ball. The powder was a phony one, RS Pyro--x of 100gr. stricken measure.
Had I been his guide, I would not have let him shoot as I witnessed his shooting in camp, wherein he barely kept 3 shots on an 10" x 14" target at 100yards from a bench.
If starting at 1,800fps (wild guess)I figured the ball's vel. at 170yards at about 850fps with an energy of approximately 360 foot pounds. The moose took off like a horse out of a starting gate and dropped dead after covering 40 yards- mere seconds after receiving the hit.
The ball went through a rib on the impact side, through the left lung, centered the heart, holed the right lung and stopped against the hide on the far side.
There was a 1/2"hole through those vitals. I was as surprised as anyone else.
Forsyth noted he'd penned both shoulders of a Sambar Sag at 250yards, with his 14 bore sxs rifle, a single shot. He was prone to using hardened lead, usually with tin or mercury & 4 to 4 1/2 drams of #6 powder.
I will also note here, that his .54 barrel died before a year was up - totally rotted out by the pyro powder's acidic fouling. He then had Taylor build him a .54, .40 interchangeable barrel rifle, then a .32, also in English design. He destroyed all 3 of those barrels with that powder, as he insisted upon using it.
He did not believe Taylor nor I about it being harmful, until he later contacted Mike Nesbit, I think it was, who also told him it was death to his barrels to use it & it would indeed, eat a hole right out the side of the barrel, once it started the cancer.
