Green Mountain use to make “Drop in” Barrels for the TC Hawken and Renegade. They did so in Fast (Bullet) and Slow (Roundball) Twist, From .32 to .58 Cal. They made These Barrels in both 15/16” and 1” Across the Flats. Your .54 Hawken stock is 1” the .45/.50 Hawken’s are all 15/16” And ALL TC Renegades were 1”
You can stil find these things from time to time, but they can bring a MINT though. If you do a Search on Ebay For Green Mountain Barrels there will likely be something on there. It seems like the Going price when you find 1 of these in New, or like New condition is 250-300 Bucks. You might check Track of the Wolf for a GM Barrel, I believe they Stil Have some? But might be 15/16” only though?
The Fast Bullet Twist line of these GM “Drop in” Barrels Will have an LRH after the Caliber, The .45 LRH is 1:30 Twist, the .50 and .54s were all 1:28 Twist. The Slow Roundball Twist Barrels will Just say the Caliber, and I believe are all 1:70 Twist? I don’t own any of the Roundball Barrels (Wasn’t my interest) But i do own all but 1 Fast Twist Bullet Barrel that GM made. They made a “Sharp shooter” Barrel in .50 Cal 1:24 Twist, i never could get my hands on 1 of these. They even came with a Malcolm Scope. Toby Bridges is the only person i have seen with 1 of these, But I know others had them. A friend of mine in South Dakota Owned 1 of them.
Rice Barrels is another Outfit that can/will make a “Drop in” Hooked Breech Barrel for a TC Stock. I own a Fast 1:20 Twist .451 Rice “Drop in” Barrel, i have it in an Old .54 TC Hawken Stock. My Rice is 1 of the most accurate Sidelock Muzzleloader Barrels i own, I give it a Slight edge over my Green Mountains. Rice is Expensive (400 or so) But they are DARN Good Barrels. Good Luck! You will Find a Barrel :Red tup:
As mentioned above, Robert Hoyt can Rebore a Barrel and Put whatever Twist you want in it? So this is definitely an option, He can even Re Line a Barrel. He Did one for me back in the Winter, it was 120 bucks plus actual Shipping back to you. When you Receive the Barrel back it will have the Bill with it, That was the way it was with mine anyway. I had to spend quite a bit of time polishing my Hoyt Re-Bore, is was on the Rough Side.