I got a new 300 Blk upper. Put some new Magpul MBUS flip up sights on it. I'm trying to bore sight the weapon now. I painted the laser point of impact on the bullseye. Viewing through my iron sights I find that I can't adjust the point of aim to match the laser mark. The point of aim is about 2 3/4" above the point of impact. My iron sights have provisions for adjustments but I can't get into the point of impact. I'm fairly new at this and I'm pretty well stumped. Can someone please offer some assistance and thanks in advance.