I experienced this when my boys started shooting prone, and then again as we taught others to shoot long range, using our equipment. How we fixed this. First, we wrote down notes on exactly how we get into the rifle, step by step, finishing with shoulder relaxed, dead weight in to the rifle with light repeatable bipod loading. When other men followed these instructions, they were able to accomplish nearly identical point of impact. We explained that its not that they are doing anything wrong, but this is how are rifles are zeroed/ dialed in and to make good hits this is what they needed to do. For the boys specifically, they were unable to apply enough dead weight into the stock, and they always hit higher than we do, when following the same instructions. So we zeroed there rifle with very little, almost no dead weight. They can duplicate it every time and have consistent point of impact. When I shoot the rifle dialed in for them, I have to remember to put less dead weight into it. If I do, I can achieve the same point of impact as they do. If I get into the rifle the way I normally do, I will hit low every time. I thought about redoing my rifles for less dead weight so they are the same, but prefer a little more dead weight for spotting my own hits consistently. As they get bigger I will work with them on this so eventually, they are all dialed in the same. The biggest thing is determining the amount of dead weight/ bipod loading that can be done consistently every time, and then zero the rifle using that method. Having gone through this and finding a solution, I hope this helps.
