Originally Posted by pestobanana
Yeah, MP5s require you to take the stock off and such.
Stuff like APS and Ares M4s and Amoebas have quick change gearboxes, but the bodies are built so that you can't access the spring guide until you strip the gun down to the gearbox anyway....
I'm confused... the KWA ERG is an M4, it's the electronic recoil gun. Taking off the rear buffer tube is simple (doesn't use a screw on the inside but the nut like a RS gun) the, then the spring, recoil weight and recoil spring all come out together. No need to open the receiver or the gear box.