Weird accuracy problem July 15, 2021, 06:41:05 AM Aero Precision M5 upper and lower. Criterion and Oden Works barrels have the same issue. I get 2 groups 2 inches apart depending on what side of the mag it feeds from. Each group would be a 1/2 or less on their own. Tried multiple brands of magazines, swaped complete lower from my 308 build. Also swaped bolt and carrier, scope and mount, buffer and spring. Anyone else have this issue? Thinking about trying a New Frontier Armory upper next. All barrels passed the go/nogo gauges. Both factory and reloads shoot similar.