[Akami]

Okay context lol

I am thinking of doing DIY SSG, and when it comes to the cylinder, which do you think is better, big diameter or long length?

Personally I want to use TM L96 length cylinder to keep the gun short so it could be put in storage easier, which means I'll use big diameter.

But what do you guys think?

 

[RonSwanson]

My current theory is that a longer cylinder is more air efficient than a shorter wider one. (Assuming air volume is the same).

Because it's longer it should take longer for the piston to release and reach cylinder head (so use all air volume). Also as a side effect with a more efficient setup weaker springs can be used.

Now only proof of this I have is the fact that type96 rifles can use longer barrels than a vsr even though they have slightly less volume. And a longer barrel is theoretically going to provide more output energy if matched to cylinder air volume correctly.

But again mostly theory at this point as no one has truly tested

 

[Sodium]

Longer is more efficient. The aps rifles with longer cylinders, while not doing as well as the vsr, do much better than they should based on 1tonne's cylinder calculations. That said, more volume always helps too.

 

[Akami]

So in theory APS2 system with as much volume as a VSR could perform even better than VSR?

 

[RonSwanson]

So in theory APS2 system with as much volume as a VSR could perform even better than VSR?

Wouldn't say better more like more efficient as longer barrel that can be used effectively=more time for bb to gain energy=lower powered spring needed=quieter and easier.

Logically I would assume that a minimum air volume is needed to launch each BB weight (heavier=more volume) but no on has tested that yet and both platforms handle current weights without issue it seems.

Wonder if anyone with a striker could chime in if they've had trouble with heavyweights.

 

[BlackDogAirsoft]

Previous thread where we talked about this:

Interesting article on Air rifles...perhaps applicable...

The article discusses how altering piston weight and cylinder volumes can make an air rifle more efficient. Curiously, the cylinder volume is decreased, and the piston is lightened. https://www.airgunmagazine.co.uk/features/a-perfect-formula-airgun-design-breakthrough/

www.airsoftsniperforum.com

 

[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.

 

[Akami]

you may need an extra-long inner barrel to match the cylinder to barrel to bb weight ratio.

What if I use wide bore like orga?

The advantage of this is that the piston will accelerate more

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

 

[SiliconeSword]

The use of a widebore seems a bit of a waste, as you could simply just use a weaker spring or port the cylinder(last resort option) and achieve similar results but with either a better bolt pull or less sound.

 

[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.