I bought a 1903A3 with a 2 groove barrel last winter. I tried PPU 150 grain bullets. I sighted it in at 25 yds but I couldn't get any kind of group on the target at 100 yds. I even had a keyhole at 25 yds, never had that happen before. I switched to Greek surplus M2 and it groups now but shoots about 13-14 inches high. The sight I have is approx. 3/16" tall. I don't see any letter on it. The rear sight is pushed down to the 2 mark. If I aim at the bottom edge of an SR1 target and put the top of the post at the very bottom of the peep (where I can just make it out) I can hit the black. Any idea how tall of a front sight I will need to find? Thanks