I also have a .54 caliber T/C Renegade which was a kit about 20 some years ago. It also has a 1-48 twist. I found that 80 grains of Pyrodex RS, a .015 lubed patch (not pre cut in my case) and a hornady round ball is an accurate load. I also shoot LEE Bullets I make. They are 300 grain conicals. They are really accurate with 90 grains of Pyrodex RS under them. I have shot the 426 grain Buffalo Bullets, and they are fine with 90 grains of Pyrodex RS. I shot ballets once, and they were real accurate with 80 grains of Pyrodex RS. I shot sabots once out of it. They seemed to shoot all right, but I do not like the plastic they leave in the barrel. You can order a replacement barrel from Green Mountain, but I see no reason to change caliber. I think if you hunt with the .54 caliber, you will find it very accurate, and hard hitting. I have taken deer at 80 yards with a round ball, and shot right through them, and dropped them where they stood. I have hunted and shot deer with this rifle for the past 20+ years, in my opinion, you got a great rifle right there...... good shooting. Keep a journal of your charge and loads, it comes in real handy for future reference......
