Extra-large diameter muzzle replaces the bushing for greater solid barrel/slide contact area and improved lockup. Ultra smooth rifling provides a precise bore that delivers exceptional accuracy and higher velocities. Bores are air gauged to ensure a maximum of .0002" bore tolerance. If converting from a conventional bushing-style barrel, a reverse plug must be fitted to your slide. Pre-fit (PF) includes link and pin; features fully fitted bottom feet and hood. Installation requires minor fitting. Also available in Nowlin Shop dimension (oversized hood length 1.314-.002 and hood width .370-.002, feet O.D. 1.028+.004). We currently don't have Gunsmith in stock.