I have a pair of AR Stoner Uppers. One is a factory built 20", the other is a 24" homebuilt using AR Stoner parts.
The
barrels are from AR Stoner stock, a Midway in-house brand name. Various builders are suspected; one was Bear Creek. Some credible suggestions are Liberty, a button rifled division of Satern.
Once set up and being prepared of first outing, both the 20" and the 24" were borescoped using the Teslong unit. No obvious blemishes were noted.
Load testing is in progress, and a barrel contact issue was found and fixed for the 24". Too early to cite group diameters, but it looks like Sub-MOA is a real possibility. How much "Sub-MOA" will turn out to be is still undetermined.
Loads are being tested with the Speer 90gr TNT, Hornady 95gr V-Max, and Speer 120gr Gold Dot; with W748 for the propellant, Starline Brass, and CCI/Win Primers.
Greg