I have used X-caliber, Shilen, Douglas, ER Shaw, Criterion, Pac-Nor and have smiths prefit Hart, Bartlein and Kreiger tubes. All have shot well, some better than others. All would run under .5MOA a long ways out and a Mcgowen 7SAUM I got off a member here throws 180gr Bergers at 3100 and shot 17...