[1tonne]

One thing to think about with a longer, wider cylinder that has more volume, is that if there is too much volume, you may need an extra-long inner barrel to match the cylinder to barrel to bb weight ratio. But this is OK because you can then port the cylinder. So, you can then shorten the barrel to a desired length and then port the cylinder to have the correct amount of air for the barrel and bb weight. The advantage of this is that the piston will accelerate more before compression starts. Thus, giving you very high fps with a lighter bolt pull.

 

[1tonne]

What if I use wide bore like orga?

You could use a wide bore if you wanted but wide bores are a waste of energy. I have found no difference in accuracy between rifles of the same energy rate that have different bore diameters. Some people say otherwise but I have never noticed it and I have done hundreds of experiments.

Wouldn't it affect the ideal joule output? You know, the correct piston weight thing, where we want the piston to move not too fast and not too slow

I don't think that a high piston speed makes the rifle inaccurate. It is more if the speed of the bb is too much for its mass. (This could be incorrect, but it is what I think at the moment unless someone can convince me otherwise). So, on these forums you will see a lot of people say that any rifle shooting above 4 joules is not worth it (unless using ceramics). So, to bring the speed of the bb down in a rifle that has excess air, you could port it to have the perfect volume for the bb. You can then use a weak spring to get a high energy rate because the piston has already sped up more than it would have if the cylinder was un-ported. Thus, making the rifle easy to rack.