So a question for Mr Blackbeard if I may....

If there any point at which a reduction in piston weight cannot be compensated for by more spring ?

E.g. today I had a 75mm stroke, 25mm bore TX with a 5.5 x 3.8 port, full length (13") .177. Set to about 11.6, but more initial recoil than I wanted. No slam, just right in that respect.

I reduced the piston weight (by est around 35-45 grams), and power dropped to around 9 FP. I then stuffed in a spring (had to be trimmed 'cos it was initially oversprung) and got back to exactly the same power, (which is believe it pretty close to the limit for this stroke in this gun) - also without slam. Noticeably less recoil and faster, but (obviously) more cocking effort. However as the spring is longer, with more preload (essential to counteract the bounce with the slighter piston), I'm not sure whether the total energy delivery by the spring is that much higher then before (i.e. the work done in compression), or if it's just a perception due to the higher initial cocking effort.

The question then being, beyond hitting practical limits of how much spring you can actually fit in the gun before it gets coilbound, is there some point when power becomes much harder to compensate for with a stronger/longer spring when reducing piston weight ? I'm guessing it's non-linear in some fashion, but you are the man for the models

Cheers - JB