The short one is good. There's a clear vinyl pad in the cylinder on the head. It works good as a sorbo pad protector.

 

I use shorter barrels than that in my SR25. I would suggest just a 250mm long inner barrel. Cheers

 

If it's too short it would be overvolumed.

Stick with the 375 mm. It's more maneuverable and should be fine with the given cylinder volume.

 

In my SR25 (2.5 cylinder), I tested with different barrel lengths using different bb weights and with 0.3gm, it had the highest energy rating with a barrel length of 255mm.
So that is the max energy that I could get from my rifle using 0.3gm bb's.
There is also a theory that the bb has to be in the barrel for a certain length before it stabilises. From what I recall the length was 430mm's. But in my opinion, this magical 430mm length of barrel was tested with light weight 0.2gm bb's. My guess is that a heavier bb like a 0.3gm bb will stabilise a lot quicker since it is heavier and so I aim for the maximum energy rating in my rifles.

 

Out of curiosity...what FPS, inner barrel diameter and hop-up setup are you running?

 

It was around 420fps. Diameter was 6.01mm. Sorry, I cannot remember the bucking. Cheers

 

Just a little update for anyone else:
With :
this one-piece SHS full cylinder,
SHS polycarbonate lightweight piston (blue, windows cut on sides)
SHS POM piston head with bearing
Guarder 130 spring
375mm 6.05 PDI barrel

I got around 445 with 0.2 and around 375 with 0.3.

I am amazed how good it came out, just under field limit with 0.2 and just under "conscience" limit (2J) with 0.3.

I am using 16:1 SHS gears with Lonex Torque&Speed motor and RPS on 7.4V li-po is under 16 RPS which is just enough.

I will try the 300mm barrel to see what will be the difference.

 

I will try the 300mm barrel to see what will be the difference.

Shorter barrel will most likely mean you will need a slightly bigger spring to get the same results.