My first Grendel / AR Stoner barrel / range result

[XOOFP]

That's why I bought it. I was betting on the piston system being the problem. Everything I have read indicates piston guns, in general, are likely to suffer a decrease in accuracy due to the additional mechanical disturbance, although there are certainly some exceptions. Sub-moa at 300 yards would be great. I hope it happens. Might be too much to wish for.