http://www.airsplat.com/Items/AC-UPI-WE-OBKIT.htm
In this two part AirSplat Tech Tip video series we show how to take down and install a WE TECH OPEN Bolt Conversion kit for the WE Closed Bolt M4 Gas Blowback Rifle (GBBR). An open bolt blowback makes for a much more realistic action when shooting the WE m4 GBBR. Airsoft tech Max goes over step by step the take down, installation, and reassembly of the bolt assembly, lower trigger mechanism, as well as converting the magazine to feed open bolt magazines. This Video will demonstrate installtion of the upper components