As you say, the 1:48 is a compromise twist rate, good for conicals andround balls.

I have shot T/C Renegades and others in 1:48 barrels for years. They shoot Maxiballs very well. IfI were you I'd scrap the round balls and ball-ets, and similar bullets, and go toreal conicals like the Maxiball and great plains bullet. These bullets are serious deer killers.

Your gun is made to use pelletsor loose powders like pyrodex, and of course real black. It is not supposed to be fussy. I'd go withloose yrodex RS or P, and I'd start at no less than 80 grains. I'd try to get to 90 or 100 for a hunting charge, but stick with what is most accurate. I would be very surprised if you can't get far better accuracy and range than you are seeing with your current load and bullet.I can't really advise you on priming charges, but from what little I've heard 3f or 4f can be used.