thats a great gun!
Goex would be the best for instant fire. Pyrodex RS or Pyrodex P is pretty good in it as well.
.018" patch, start off with 70 grains powder and see how that works. Clean between each shot as well.
The mountain stalker can have anywhere from a 1:32 to a 1:38 twist and should be stamped in the barrel.
If the ball doesnt work, a 295gr powerbelt aerotip does wonders in the accuracy department.
