Perhaps the nearest thing to an Inokatsu build are those airsoft rifles made by Vipertech from Taiwan. In this video, Nextgen Retros goes over their Colt M16/M16A1 Vietnam Model 603 Gas Blowback Rifle... "One of the best M16 GBBs on the market. Forged body and a lot of steel parts. I need for the future an A2 Upper Assembly too!"