ULTRA RIFLED #3 CONTOUR BARREL BLANKS Famous, Douglas Double XX, premium-grade barrels are an excellent choice for any rebarrelling project. Proven accuracy and finest care in manufacture. Button rifled for unequalled smoothness with tolerances for groove diameter and straightness held to .0005". .22 through .338 barrels feature 6- grooves while the .358, .375 and .458 barrels have 8. No straightening is done and all barrels are stress relieved. SPECS: 4140 Chrome moly and stainless steel. Unturned Blanks will be .025" (.63mm)-.050" (1.3mm) larger in diameter and 1-?" (3.8cm) longer than shown. Not threaded or chambered. Mfg: Douglas