Hadron Airsoft Designs put together the SRU APX-01 Kit and installing their LOKI TDC Unit... "Here we unbox, review and assemble the SRU APX-01 Carbine kit. During the assembly we install the LOKI AAP TDC hop unit, and drill the carbine kit upper.

Its a long video, (apologies) with quite a few details to cover. I have tried not to cut much out, and there was no practice run. I find trimming videos down, can sometimes loose the lessons that are learned.