Curious if anyone has had the same issue.. I have a 50 cal Bone collector and can't get it to zero at 100 yards. It shoots about 4-5" low, the windage is good. I have tried loose powder and pellets from 100-150 grains. I have shot multiple brands of bullets. I clean it after shooting it. It groups well just low. I have had other people shoot it with the same result. I have contacted the manufacture and that was a dead end. I also bought a new rear sight that was a little higher than the stock sight, it gained some but still low. Ideas??