Does ammo vary THAT much? I had some Remington Match Grade (I believe) 165 gr that I used to sight in the scope at 100yrds I was able to consistently nail the target within a 3" group. And for ME, that's phenomenal! I then switched over to some 150 gr PMC target and was utterly SHOCKED. I couldn't hit the center of my target for crap. And I was anything but consistent. I was 4"-6" to the left and down, then 5" to the right low. This continued for 10 more rounds. I switched to some magtech.....not even sure what grain (package didn't have info) with the same results as the PMC. Kinda all over the target nothing consistent. Switched back to the match grade, and 3" dead center again. WTH?!?! BTW.... Bushmaster BR-308 MOE