Trade Musket shoots low...........

[Mr. 16 gauge]

................WAY low!!! I got out a few weekends ago and tried my Cabelas trade musket with some round balls that I cast. All I can say is I was extremely disappointed in the results. The balls were cast with a LEE mold (.600 round ball) and weighed so that they were within one grain of each other. Patches were .010 Ox-yokes, and I tried just about every combination I could think of: over powder wad, felt wad, patch, over shot wad, over powder wad, felt patch, patched ball,; overpowder wad, patched ball; patched ball only, ect. I tried both FFg and FFFg from 60 to 90 grains (each) and I still couldnt put a ball in the target (including the bloody backstop! ) at 50 yards! At 25 yards, the balls are shooting low, about a foot from point of aim. I am a bit distressed at this, as I did want to take it big game hunting from time to time. I know I can file down the front sight, but when I look down the barrel, there doesn't seem to be that much front site to begin with......any suggestions other than "guesstimating" where to aim above a deer's back? On a postive note, I did try the gun on clay targets and broke about half of the ones I shot at (when the gun went off....it was pretty fouled at this point), so I am confident that I can reasonably take small game with it this winter, if I get a chance to go out. Thanks in advance for any insight...........