Airsoft ᗰᗩᖇᔕᕼᗰEᒪᒪOᗯ explains how he went about with this build in this video... "For the Improvement, I have finally got to work on the Bolt AEG gearbox shell. Since the start, I have had this Bolt AEG to work with. The gearbox shell has been a nightmare from day one. Mostly, align everything when putting the box back together; last time it took multipul tries and a few hours to get it done.

I decided to take on the challange of change out the stock shell and go with a Quick Change Spring gearbox. I tossed may ideas around my mind as to what box might work and what would be within a reasonable price. After a few months, I turned to the King Arms Version 2 8mm Gearbox with Quick Change Spring Guide.

Lucky enough it fit the AEG phyiscally without a issue, however,.....the internals needed some mods for my build.

I ran into issues with using the Krytac trigger, the piston, the Lonex M120 spring, and couple other fun stuff. Tech work on a gearbox is tough enough, but changing over parts from one to another,......lets just say I can cross that off the list.

It had its challenges, make no mistake.

Though, it was not impossible."