Budding airsoft gunsmiths looking into building their M4 airsoft guns can check this video from Efdé90’s Airsoft Channel. Sometimes it's pretty daunting but when you get the hang of it, it is also sheer joy to see the results when you complete your build. Just make sure that the parts you acquire are compatible before you set out on your own build... "Hey there, welcome back to another video! In this video I'm building a custom M4 airsoft gun from scratch!"