The gearbox shell inside my Dboys HK416 is definitely a clone of the VFC gearbox shell that I recently got. It is compatible with the VFC bolt stop mechanism that attaches to the right side of the V2 shell, as well as has the same anti-reversal latch release hole cut out on the left side of the shell.
Only major differences? Black paint job on the Dboys shell, and 7mm bearings in Dboys as versus the 8mm bushings in VFC. Heck, the Dboys shell cracks just as quickly and in the same place as the VFC one does – mine developed a nice fracture near the cylinder head last week, after I pulled it out to play with on Sunday.
Without any other “reinforced” V2 gearbox shells left in my current overstock of personal parts, I guess I’ll have to use this VFC shell until it breaks. I give it a few months on this M110 spring… I’m crossing my fingers that it lasts till the end of summer.