ROF stuff

[ILLusion]

Originally Posted by AnakChan

My setup on my CQB P90 :-

- 3 teeth taken off sector
- 1st (or last depending on how you look @ it) 3 teeth taken off piston
- 2nd (or 2nd last, depending on how you look at it) tooth taken off
piston
- SystemA Turbo motor
- SystemA M120 spring
- 11.1V/2150mAh LiPo
- Tanio Koba inner barrel to reduce FPS to legal Jpn limits

Setup ran fine for 6xwhole day games (approx 18-20,000 BB's?) before piston gears stripped :-

http://www.anakchan.com/gallery/Hobb...2_enterAlbum=1

Agreed mags couldn't keep up with mechbox setup. Actual ROF was as high as 34/sec but would love to test ROF from sound :-

http://www.airsoftmechanics.com/home...nt/view/24/30/

Just because you install that inner barrel, it doesn't mean your velocity will go down. Your BBs will just shoot wild at the end of their effective range, although at 380-400fps.

That inner barrel is only recommended for guns that will output 1J of power (328fps). An M120 spring far surpasses that.

As for the damage on your gun, the stripping of the initial tooth on the piston suggests either:
1. The spring is too heavy and providing too much resistance against the fast moving sector gear
2. The piston is still moving too slow for the sector gear and is getting the rear teeth raked

Scenario #1 is the more plausible of the two. Although, having it run for ~20,000 rounds with that setup is pretty impressive!

[AnakChan]

Hi ILLusion,

Ah..apologies, I should have been clearer :-). When I trimmed off 3xteeth off the sector and off the piston, I've created a shorter piston stroke (therefore increasing ROF). So with the M120 spring, I'm actually getting less than 328fps...in fact I'm getting 0.96J only.

Here's what I mean :-

http://www.anakchan.com/gallery/Hobb...2_enterAlbum=0

Note only 13xteeth on the sector, and the length of 12xteeth on the piston (but spaced out to an equivalent to 13xteeth - the 2nd was removed to reduce crashes).

You're right for the reason of the crash. Even though I've taken the 2nd tooth off, I think I still run the risk of crashes. I may consider removing the 3rd tooth too (or simply run with a lower voltage battery since my mags can't keep up with the mechbox setup anyway).

[ILLusion]

Not sure if removing the 3rd tooth is a wise idea - a lot of stress would be put on the 4th tooth.

[AnakChan]

Doh! That's why the last tooth of a standard piston is metal (which I filed off). Well let's see this time if it lasts ~20,000 rounds as well. Maybe I was just lucky with the previous one (same config). After this, I'll switch over to the Angel Hi-Speed Piston/Phoenix Hi-Speed auto shimming Gears (both 12th teeth setup as standard from manufacturer).

Cheers for your advice though ILLusion!