I'd check out some of Randy Wakeman's articles online, he has a lot of experience with different loads in Thompsons. I think his preferred bullet out of a TC is the Barnes TEZ 250 since TC's generally have a tighter bore. Get yourself a SpinJag loader also, they're wonderful.
I am somewhat leary of Mr Wakeman's ideas on ideal bullet design. I have read a lot of his articles, and have come to the conclusion that the deer that he shoots must have Kevlar hides and titanium bones. Ok an exaggeration, but in reality his perspective seems to be if your bullet cannot pass through the animal you are hunting lengthways, puncturing the pelvis, and exiting through the brisket, then it doesn't have enough penetration...even the 150 grain spire point coming out of my weatherby 300 mag won't do that, and I have had a total of 3 deer in 10 years go more than 10 yards after being hit by that thing.
While I agree that you need penetration, I personally want every ounce of energy (besides maybe just enough to push it through the hide on the opposite side) spent in the animal, and I want the bullet to expand as much as possible without going to shreds. From what I read of him, a bullet Mr Wakeman recommends is not going to do that.
My own personal preference, after my father and I's experimenting with a various different sizes and styles of projectile has come to be a 245 gr powerbelt hollow point with 100 grains 777. (wakeman btw abhors these rounds).
You get pass through the majority of the time on broadside shots on normal sized deer, if you are passing through the ribcage. IF you pass through the shoulder, the bullet usually lodges in either the opposite shoulder, or the hide if it is an angling shot. I hunt primarily in an area bordered by a lot of thick cover, so I don't want them going far. and with this bullet all but one of my deer has gone down in under 60 yards, mostly under 30.
These aren't aerodynamic at all, so if you are wanting a 150yrd + round they aren't for you. but out of my TC IMPACT they give 2 inch groups at 100 yards, and I know they are still plenty lethal at 120 yrds (my longest shot to date, and the damage was still impressive).
I know opinions on good rounds for muzzleloaders are a dime a dozen. But when I saw you being guided to Mr Wakeman, I had to share my perspective on what constitutes a "good" load for a smokepole. He is a great source for information, i just happen to differ with him on this one. Good luck.
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