Possible Piston Problem?

[Rotting]

Quick story about what exactly happened.

Was running a SiG552 with a 509mm inner barrel, properly ported cylinder, brand new piston. Was working fine for a while until I set up camp as a suppressing fire role. Went through 1.25 mags (Roughly 110 rounds) in about 25 seconds and heard that lovely noise of a stripped piston/gears. After that I popped it open in-field to see what the problem was, and there apparently is no issue. Piston is fine, all the gears are fine, pinion on the motor is fine. The only thing I noticed was that the side of the piston looked like the gears were spinning past it, as it is very slightly grazed as if something hit it. Re-aligned everything and used the stock spring opposed to my regular spring. Stock spring shoots about 270FPS, the spring I normally use shoots about 400FPS. Shot for about 5 shots, and it did it again.

Again, using this piston: http://www.airsoftparts.ca/store2/in...oducts_id=1377
Using this cylinder: http://www.airsoftparts.ca/store2/in...roducts_id=776

Two things came to mind. One being that the piston is faulty, too narrow and not properly sitting on the tracks, and therefore is rotating off the tracks of the mechbox and the piston and gears can no longer interlock. Second is a parts-co-operation issue, as the piston is MA, and the cylinder is Modify. Not sure if either of these are the issue, so I'm kind of throwing it out there.

Also, as an additional question, I am currently using the S100 spring by Modify, which I can't complain about, it works amazingly, except it's not suitable for me. I need to be able to go full-auto at times, and doing so with that particular spring causes too high of a risk of stripping the gears. Instead, I'm wondering if the S90 by Modify will give me enough of an FPS drop (370FPS with 0.20g BBs) that I won't be running the risk of destroying the piston due to an overpowered spring. Main question is will the S90 give me the drop in FPS I need and also give me the ability to at least fire more liberally?

Note that I typically use nothing but Modify internals. For the piston issue, I would like to also know if the Modify Type-0 Cylinder is compatible with the Prometheus Hard Piston, as I hear that piston is basically legendary for never breaking down on the user.

[Boyso]

S90 won't give you 370 fps.

Barely 300 from what I've tested. At least, with the compression I have.

Try sliding your piston by hand in your gearbox without all the internals. Any resistance, any wobble?

[Rotting]

S100 is only supposed to give about 370, yet I'm getting 400, so I was assuming the S90 would give me about 300-350, mind you I have a lot of air seal improvements put in so far. Having an FPS of 350 would allow me to fulfill my role (long range/anti-sniper) as well as being able to do suppressive fire when needed without destroying the gears or the piston.

Yes, there is a minor amount of wobble present. I'm sure this could be a cause as it wouldn't take a whole lot of pressure to disrupt the alignment of the track. Now it's more of an issue of "is this fixable" or do I need to just purchase a new piston.

[Amos]

Euch metal piston...

Try changing it out for a piston that's the same brand as your gears

[Rotting]

Gears are stock as they've taken a beating so far and aren't letting it stop them. That and it's worth to note that I'm running low on funds once again (go go student, unemployed). It's on the list though with the mechbox shell upgrade. Hoping to basically finish up what I started last year in a couple of weeks, just shy of a metal body (Fuck you HurricanE metal body).