I presently use 110 grs of Pyrodex behind a 405 gr. powerbelt for elk. I doubt you will every hear any knowledgeable muzzleloader recommend a certain grain in all situations. I am no expert, but what I have heard them say is to start at 90 grains and work up to a MAX of 150 grains with the bullets you will be using. Then use the bullet/powder combination that is most accurate for your gun. EVERY GUN IS DIFFERENT, and that includes 2 of the same make and model. Just like rifles, each gun has a load that it likes the best, so you have to do a lot of experimenting.

The 150 grain max load doesn't apply to the new Triple 7 powder because a smaller VOLUMN of 777 equals a pyrodex/blackpowder eqivalent. Seems like people have said to use 15-20% less 777 by volumn to get the same ballistics/velocities.