The Need to Change the Cylinder if You Change Your Inner Barrel

[[]D[][]\/[][]D]

In essence, wouldn't using a full cylinder like the Prometheus Stainless Hard Cylinder (A) or Systema N-B Cylinder Type-0 that's used for +450mm length inner barrels be the only cylinder you should use regardless of inner barrel length? The holes/cut outs on the other type of cylinders for shorter inner barrels just doesn't make sense to me. Wouldn't using a full cylinder optimize your FPS regardless of barrel length?

[zone 69]

http://arniesairsoft.co.uk/?filnavn=...andbarrels.htm

[CDN_Stalker]

Heck there was a big detailed discussion on this a couple weeks ago on here about ported/full cylinder vs barrel length.

[[]D[][]\/[][]D]

Originally Posted by zone 69

http://arniesairsoft.co.uk/?filnavn=...andbarrels.htm

I already know that information that they mention. I just wanted to know if using a full cylinder would be more logical (performance and FPS wise) than using a cylinder with holes on any length of inner barrel.

[[]D[][]\/[][]D]

Originally Posted by CDN_Stalker

Heck there was a big detailed discussion on this a couple weeks ago on here about ported/full cylinder vs barrel length.

I'll go look for that thread, sorry for asking a question that has already be discussed.

[CDN_Stalker]

Originally Posted by []D[][]\/[][]D

I'll go look for that thread, sorry for asking a question that has already be discussed.

Is ok, wasn't a flame, just a heads up about the discussion. And I'll tell you, I tried a full cylinder in my MP5 once and got a 30fps drop in velocity. And a ported cylinder in a LONG barrel would end up giving you not enough air volume through the barrel to make the BB travel at it's most efficient speed, you'd end up with 'barrel suck' or whatever people know it as, a slight vacuum is created behind the moving BB and fps drops dramatically.

[milehigh]

Apparently the fps drop with an undersize barrel on a full cylinder is due to the slower acceleration of the piston once it is released. On top of that, your BB will leave the barrel while your piston is still in motion, causing it to slam into your cylinder head, thus making it harder on your gearbox. It's almost like dry-firing.

[[]D[][]\/[][]D]

Originally Posted by milehigh

Apparently the fps drop with an undersize barrel on a full cylinder is due to the slower acceleration of the piston once it is released. On top of that, your BB will leave the barrel while your piston is still in motion, causing it to slam into your cylinder head, thus making it harder on your gearbox. It's almost like dry-firing.

Ah, that makes a whole lot of sense now!

Thanks for clearing that up with me.

[[]D[][]\/[][]D]

Originally Posted by CDN_Stalker

Is ok, wasn't a flame, just a heads up about the discussion. And I'll tell you, I tried a full cylinder in my MP5 once and got a 30fps drop in velocity. And a ported cylinder in a LONG barrel would end up giving you not enough air volume through the barrel to make the BB travel at it's most efficient speed, you'd end up with 'barrel suck' or whatever people know it as, a slight vacuum is created behind the moving BB and fps drops dramatically.

That 'barrel suck' or whatever you were talking about kind of confused me a little. LOL

[CDN_Stalker]

Originally Posted by milehigh

Apparently the fps drop with an undersize barrel on a full cylinder is due to the slower acceleration of the piston once it is released. On top of that, your BB will leave the barrel while your piston is still in motion, causing it to slam into your cylinder head, thus making it harder on your gearbox. It's almost like dry-firing.

Yup, exactly! BB is gone before the full power stroke of the piston.

Originally Posted by []D[][]\/[][]D

That 'barrel suck' or whatever you were talking about kind of confused me a little. LOL

Is all about internal air volume. If your cylinder has an interal volume of say 8 units and your inner barrel has a volume of 12, once the BB gets to the point of 8 units of air, there is no more pressure after, it drops off very quickly, and the BB will keep moving forward regardless while the airpressure behind it keeps dropping, hence the 'vacuum' I mentioned. Some think the suck thing is the retracting piston (in full auto fire) pulling back on the BB but barrel suck happens on bolt action rifles too with extrememly long inner barrels.

Sorry if this is a confusing description, I just woke up. Lol