I swapped my Bushmaster xm 15 es2 to a friend for his DPMS h-bar flat top. So, yesterday I took it out with a handful of rounds I had around. I set of a target @25 yards and bang bang bang. NO HOLES IN THE PAPER =). Oh well I said I'll adjust the Irons. I turned the rear all the way down and repeated the process. Still no holes in the paper. So I start Turning the front post up Bang bang bang . Can you guess how it went that time? Same I am going to get a shorter front post. Now I have another excuse to burn some more powder. Life is good.