PDI 01 Inner Barrel for Western Arms (WA) M4A1 Series (509mm)

PDI barrels are cold-hammer forged from stainless steel, which is the same process how real rifle barrels are produced. They have a superior tolerance and roundness of the inner surface compared to anything else on the market. Internal diameter 6.01mm built for precision shooting Genuine Products by PDI Stainless Steel Tightbore Upgrade Barrel Advance Technology forming by Cold Forging on Stainless Steel result in tolerance no more than