An upgraded, ported rear piston head for the KWC CO2 Uzi. This provides a better seal with the brass cylinder than the stock factory part which is a very loose fit. It helps reduce gas consumption and will also restore blowback strength.
Fitting instructions:
1) As this provides such an efficient seal, 1 or 2 small holes are usually needed to be made in the brass cylinder (as per the pictures). Otherwise the gun will cycle on semi and feed bb's but on full auto the nozzle doesn't have time to return to position to pick up a bb so the gun will fire fine in full auto but is unlikely to feed bb's
2) The grub screws provided replace the stock pin that holds rear piston head in place. These need heating up in a lighter flame for 5-10 seconds and then they will widen and self thread the stock pin hole as you screw them in either side.