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.
This inner barrel is suitable for the Western Arms M4A1 Series . Made of SUS304 stainless steel, inner diameter is 6.01mm and outer diameter is 8mm.
This product was added to our catalog on Tuesday 02 September, 2008.