Your load will depend on the kind of projectile you want to shoot. Some of them you will find will do better at 100 grains. Others might do better at 120 grains. It is all a matter of trial and error. That is why a lot of shooters use loose powder. We custom the loads a little easier to fit the projectile. You will probably find that most of the projectiles you shoot will do just fine with 100 grains or two pellets. There is no sense beating your self up and wasting money at the same time with the 150 grain charges.