Most gearboxes are Tokyo Marui compatible. I believe M60s and M249s use short length motors. Check airsoftforum.com for more information. If you want to shoot a 300 spring, and you want a gun that does not break quickly, you need gears with a higher ratio than standard gears, and a battery capable o...

Thanks for the responses. I am hoping to avoid purchasing a palmers regulator due to the high price and ebay seems to have a few alternatives: http://www.ebay.com/itm/Spyder-Paintball-Gun-CO2-HPA-Air-Gas-Regulator-Bottomline-Drop-Forward-BLUE-New-/300648350246?pt=LH_DefaultDomain_0&hash=item460009c2...

So here is my design for a 6mm qev semi automatic. Its only notable difference from normal qevs guns is its use feeding nozzle piston constructed from a blow gun nozzle. Operation: A: Check valve is open, gas flow in, this pressurizes the gas chamber and the feeding nozzle, which is pushed forward u...