Fixing the dreaded full-auto operation while in the semi-auto position

So I recently encountered an issue with my KWA M16BR where it would fire in full-auto despite the fact that I had the selector switch in the semi-auto position. I broke the replica down, made sure nothing was obviously damaged, fiddled around with a couple of parts, then finally abandoned all hope and decided to ask for help.

For anyone who’s encountering this issue, take a look at one tiny part inside your gearbox, namely the cutoff lever. In the picture below, this part is the funny looking thing directly below the bearing pack at the middle left side of the screen.

In my case, this part was not tightly screwed down, and therefore ‘wandered’ whenever you moved the selector switch. I tightened the screw down with some loctite, reassembled the replica, and presto, everything appears to be functioning normally.

Of course, if you’re not comfortable with the level of deconstruction required to do this (you will be completely disassembling the gearbox to get to this part, there is no other way), take it to your local airsoft shop or airsmith and they’ll get you back up and running. It’s not for the fainthearted, and it requires some ability to memorize the order in which parts come out of the box (and where exactly that spring went when you foolishly removed the anti-reversal latch).

If you want to become comfortable with this level of destruction, I highly recommend the videos at mechbox.com, specifically this one: V2 Mechbox, Spring Upgrade. Pause it from time to time, rewatch it a couple of times, and you should be good to go.

As always, anything that happens is not my fault, and don’t come here expecting me to make things right when you screw something up.