How many groups were fired at 100 yards? Was there any wind?

Sounds like the gun did great-- you said the bullets were in the same place. I' d write off the 6" to windage, and suggest you sight the gun in about 3" high @ 100 yards. (2.99" for a 150 yard zero as below.)


.50 cal 295 gr Copper Clad AeroTip BC=.186 150 grains
Distance (yards) Muzzle 25 50 75 100 125 150 175
Velocity (fps) 1924 1825 1731 1641 1557 1476 1400 1328
Kinetic Engery (ft lb) 2313 2081 1871 1682 1514 1361 1223 1104
Trajectory -1.5 0.7 2.23 2.99 2.98 2 0 -3.07