Recommendation of a bullet is a very hard thing to do because these muzzleloaders tend to have personalities of their own. What one might like, an identical might not group worth a darn. When people are looking for a projectile, or I am trying to work up a new rifle, I always start with known performers. I like to get some 240 grain T/C Mag Express XTP's and some 300 grain Hornady XTP's. I also like to get some 250 & 300 grain Shockwaves. Then its a matter of starting with about 85 grains of a quality performing powder like Triple Se7en, Pyrodex, or Goex and working up the load to see how they behave. Out of those four projectiles, I can usually find one that will produce some very impressive groups. Also all of them make an excellent hunting projectile...

Good luck with your rifle.