Quote Originally Posted by Shed tuner View Post
that is not going to be a port problem. A 2.8 mm port will (just) support enough flow for 12 FP.

My guess is your pistons are accelerating way too slowly, so the pressure in turn builds way too slowly, and kills power. You could either lighten them, or get stiffer springs (the total energy when compressed need not be higher, but they need to get up to speed quicker).

Or you have a massive air leak someplace, but I figure you'd have sorted that...
Acceleration is definitely a bit slower than planned. about 20% less than my TX for example. Good thinking. Should be easy to test too as as I can just run the single working piston, half the weight and double the acceleration. Unfortunately I don't have any stiffer springs, so might need to do some spring shopping.

I've had big air leaks from the breech seal, and the breech plug so far. Both of those are sorted, but I'm not ruling out piston seal issues just yet