Originally Posted by Tench
I had a play with one of these last year, i found that a lot of the gas is wasted due to poor fit of the components down stream of the firing valve. i made new parts which included an extra o ring seal so that both sides of the magazine where sealed, i also relocated the hammer spring guide fulcrum on the hammer and improved the alignment of the magazine to smooth the pellets path into the barrel. These improvements raised the power from the 1.5 ft/lb it produced when i got it to close to 3ft/lb and improved the number of shots from a bulb. The trigger can be lightened with some sear work and polishing but only on the single fire mode as in auto it has to push the hammer back.
Hey Tench, thanks for you input most helpful, the mods sound interesting how did you get to fit the extra "O" ring on the other side of the Mag?