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.

PDI Palsonite 01 Inner Barrel for Marui Hi-Capa 5.1 (Black)
Internal diameter 6.01mm built for precision shooting
Genuine Products by PDI
Suitable for Tokyo Marui Hi-Capa 5.1 Series Airsoft Gas Blow Black GBB Pistol
Choose this barrel to suit your Airsoft model
Perfect for tighter grouping & more accurate shooting

Inner Diameter : 6.01mm