hey guys, i have a NF NXS 5.5x22x56 i shoot it on a suppressed SR-25, after a good cleaning i foul up the barrel while gettin her zero'd @ 100M, when i hit the AR500 anywhere from 200-1000 i use my ballistic calculator for the values i need to dial for elev, and wind, it shoots MOA when i move from one target to another. My problem is when i dial it back down to my 100M zero and i shoot after range time, to make sure i'm G2G, it seems @ least 50% of the time my 100M zero is off an inch or so, still drivin tacks so its not the gun, i have a NF 20MOA unimount and have the torque wrench so all the screws and nuts are torqued to setting, just wondering if anyone thinks its my scope? or my barrel is fouling more after shooting which is changing the impact?