With a Bar-Sto Barrel, shot groups of 1-3/4" to 2" at 25 yards are possible with match grade ammo. Barrels are machined from stainless steel bar stock which has been heat treated to 180,000 psi tensile strength. Semi-Drop-In barrels may require minor fitting. Due to close tolerances and variances in handguns some barrels may require fitting. Most Semi-Drop-In barrels will drop-in without minor fitting. DISCLAIMER:This product is not manufactured, authorized, endorsed, or warranted by GLOCK. GLOCK does not warrant or represent that this product is compatible with GLOCK pistols.