ORIGINAL: Mossie
Yep Chap your right about the .50 caliber Rb being a little too dicey. It can work well but it sometimes does not. It's just not a big enough hole and the hole covers over with fat, and hide quickly so blood trails are faint or non existant. My deer rifles in 1/66 twist now shoot the 270 Buffalo Ball-et or a PowerBelt with ok accuracy and I don't push em real fast. The 270 grain ball-et hp has quite a performance increaseover the patched rb in my opinion. I still shoot em a bunch; but not at deer anymore and if I did it would be 50 yard head shots.
My RMC flinter is a 1/28 twist and am shooting the .452 300 xtp over 90-100 grains of 3f Goex. I also will be switching to the 300 grain Gold Dots when the box is empty; assuming they group well and expand well enough for me. Everything about that bullet is just dandy; high BC. good weight and energy; designed for the velocity my flinter would push them; bonded design and .452 flat base.
That is exactly what I am using now in my FL, 300g Gold Dot under 80g of Goex 3f, using a crushed rib sabot. Used it last year, and got a big doe with it. Very strong accurate bullet, and it shoots well in my FL at 50 yards. I really wanted an RMC flintlock, L&R lock, 1:28 twist, can shoot pellets or powder, but the price was almost $600. I got my TC Hawken, used, but almost new for $300 shipped to me. It is a great sparker and a lot of fun to shoot. I have not shot over 50 yards with it, but I am sure I could hit at 100 if I sighted it in for that. I am very confident at 50 yards and under with that rifle and that load and bullet. If you hit a deer with that bullet your goona get penetration and great damage, I believe the .50 PRB needs more mass, like your 270g Buffalo Ball-et.
Chap Gleason