Can a heavy piston rob power?

[TonyL]

Does AA put these things in an TXHC to raise or rob power, simple question

I'd say to raise power as they use the same spec spring for all calibres, it's so they can adjust the power easier, exactly the same idea that BSA use with washers in the Supersport/star.

So I guess the simple answer is that a heavy piston doesn't rob power unless using extremes

:

As Pete says.

But it's so easy to generalise, as said earlier. Some guns might benefit from more piston weight, others not. It depends on the design, dimensions, desired power and characteristics etc.

In the case of the TX HC item, this longer / heavier top hat increases weight, and therefore momentum and also spring preload. Many tinkerers remove this heavy steel item and substitute for a lighter acetal item, giving very slightly less initial recoil from the first compression stroke and a "quicker" feeling cycle but have to increase preload to restore power as this usually drops, thus quickening up the cycle even more, due to quicker piston acceleration (lighter piston / increased spring force). That extra preload will also come into play to combat potentially greater piston bounce displacement.

[Barryg]

As Pete says.

But it's so easy to generalise, as said earlier. Some guns might benefit from more piston weight, others not. It depends on the design, dimensions, desired power and characteristics etc.

In the case of the TX HC item, this longer / heavier top hat increases weight, and therefore momentum and also spring preload. Many tinkerers remove this heavy steel item and substitute for a lighter acetal item, giving very slightly less initial recoil from the first compression stroke and a "quicker" feeling cycle but have to increase preload to restore power as this usually drops, thus quickening up the cycle even more, due to quicker piston acceleration (lighter piston / increased spring force). That extra preload will also come into play to combat potentially greater piston bounce displacement.

All what you say is right Tony and I don't have that piston weight in my gun but one of the reasons that it come out was because the power was too high, I only mentioned it because I thought it was an example of a heavy piston not robing power not how the gun shot, as far as I know all of the high-powered springers have heavy pistons. I do get that the UK power limit tunning is an all-round balance

[MrGreengrass]

All what you say is right Tony and I don't have that piston weight in my gun but one of the reasons that it come out was because the power was too high, I only mentioned it because I thought it was an example of a heavy piston not robing power not how the gun shot, as far as I know all of the high-powered springers have heavy pistons. I do get that the UK power limit tunning is an all-round balance

Yes they do afaik.

[TonyL]

All what you say is right Tony and I don't have that piston weight in my gun but one of the reasons that it come out was because the power was too high, I only mentioned it because I thought it was an example of a heavy piston not robing power not how the gun shot, as far as I know all of the high-powered springers have heavy pistons. I do get that the UK power limit tunning is an all-round balance

Accepted, Bazzer.