Never tried 150 of T-7 in my Omega before I traded it off, but I did try 150gr of Pyrodex (50/50) pellets. Accuracy wasn't as good as with lighter loads, but still acceptable. I did a lot of shooting with the Omega one summer checking velocities with various loads and accuracy out to 200 yards. I finally decided 100 grains was plenty for hunting, and anything over 110/120 grains was pretty much a waste of powder (in a .50 cal).