n00b cylinder question

[Alien_Hunter]

I installed an (supposedly) m16 type ported-cylinder into my AK74, since it has a 510mm after-market barrel. I installed it correctly (cylinder away from nozzle yes?). It is 1mm or so shorter than the original (non-ported) cylinder so I pushed it all the way forward. I am asking this: do ported cylinders cause a drop in FPS to gain ROF? Am I going to get barrel suck (myth?) and is this too-short cylinder going to screw anything up? I will hopefully chrono my gun tomorrow to find out (was shooting exactly 353 w/.2). I guess more than anything I'm looking for feedback. This is the first gun I haven't simply sold after having my fun with it.

Cheers.

[PanzerFaust]

M16 cylinder is unported.
port is intended to match cylinder air volume to the volume of the inner barrel. The goal being that the bb leaves the muzzle at close to the same instant the piston slams home. Having mismatched barrels/cylinder ports could mean a potential drop in velocity as the gearbox loses efficiency. ROF shouldn't be a factor.

as for the cylinder being slightly shorter, you shouldn't see a difference, as the piston head doesn't leave the cylinder on the back-draw

[Alien_Hunter]

M16 cylinder is unported.
port is intended to match cylinder air volume to the volume of the inner barrel. The goal being that the bb leaves the muzzle at close to the same instant the piston slams home. Having mismatched barrels/cylinder ports could mean a potential drop in velocity as the gearbox loses efficiency. ROF shouldn't be a factor.

as for the cylinder being slightly shorter, you shouldn't see a difference, as the piston head doesn't leave the cylinder on the back-draw

Hopefully the local indoor arena will let me chrono it. I think my tech-guru is good for the most part but there's been a few things that have made me scratch my head a little bit. Also the metal hop up chamber I got from him is loose on my bucking. I tried the dental floss mod but I'll see what the net gain/loss of FPS is.

[Airsoftee]

Dental floss? What happened to Teflon tape?

[Alien_Hunter]

Dental floss? What happened to Teflon tape?

Floss is supposed to be better at keeping in air.

[Airsoftee]

I'll start putting dental floss on my pipe threads then…

[Alien_Hunter]

The bucking's aren't threaded so it makes sense The cylinder dropped my FPS by 50 and I got a chance to chrono my P90. . . 120 fps fml