M100 spring crazy fps
 

Kinda new to airsoft and I recently swapped out the stock spring in my version 3 gearbox as well as cleaned and lubed all the parts. I only installed an m100 spring from ace 1 arms but now I'm basically maxing out the coke can Chrono. And highly doubt it falls under the 350fps limit. I suppose I'll have to Chrono it at the field to know.

Basically I'm wondering was I supposed to use a different spring for version 3 vs version 2 gearboxes? Or will the spring calm down in power after some use

What do you mean by maxing out the coke can chrono? Is it going through the top of the can?

You can have a misslabeled spring.

BUT

The "coke can chrono" only works for the US coke cans.
Canadian cans are thinner.

Get yourself a chrono or find someone that has one before going crazy.

I had an m4 that was pushing almost 400fps 0.20 with a m100 spring. Bearing guide & head, slightly under volumed so with 0.20's it joule creeped. Was like 330'ish with 0.25's

can test chrono. ?? i used once or twice but not reliable. go to local shop for an actual cheono

I know the can test is unreliable but I haven't been to a shop yet... But it shoots through the top of an undamaged coke can with .25g elite force bbs. On another note I'm hoping to get it tested at the field this week.

Each spring has different fps when placed in different guns. This is dependent on the parts and brands more than the actual gearbox version.

Putting an m100 spring in a g&g gearbox might yield different results in another gun made by cyma for example. There's a lot of factors into determining why but it basically comes down to QC and tolerances.

The fps might setting after a few games but generally not much.

so i used the chrono at the field to test...
it was shooting about 400fps with .2g bbs.

over 3 shots it was 399, 400, 401

So what does that tell you about pseudo-chronos that don't use an actual chrono?

basic determining factors of fps in aegs (assuming no short stroke) is air cylinder volume, barrel bore and diameter and spring strength. Other factors may include if the spring guide is plain or has a bearing, if you have a spacer/bearing on the piston head and how thick it is. If your air seals are good throughout with the right setup, you can get 400 fps on a m100 spring as you have observed. This is why when people ask what spring they should get to get x fps, a good tech can't answer that immediately, they need to know the other factors, and even then that's not to say you don't get a mislabeled spring or you have a mutant gun. I've seen m100s get as high as 410 in some guns and 350 in others.

5 M100s from 5 different companies will all be different fps.
Especially these days, you have no idea what kind of gun the mfg tested the spring on, or if it was tested at all.
Back in the day we had a guy record the fps on a bunch of different springs and what we got from those companies was very consistent.
Mispackaged springs are always a risk, but even worse are the M120s that shoot 470fps because they were tested on an overvolumed g&p lol

It is what it is, either cut coils off, short stroke the piston, both, or just get a new spring.

Thanks for the helpful replies. I put the stock spring in and apparently I did something positive to compression lol... Before clean and relube with stock spring it shot 280 fps with .2g bbs. Now with stock spring, fresh lube .chroneoed at ultimate airsoft it shoots average 335 fps .2g bbs. This is first gun I have ever worked on so I'm sort of happy with this result and not really sure what I did.

Ps never mentioned but this is a totally stock asg Aug a2.