That's something one would have to see to inspect properly to determine fitment. And when it comes to gears, shimming, bushings, etc, I'm certainly no expert on the matter. I just know from experience that high speed setups can be hard on pistons, particularly if you have a high energy spring.
It seems that something is slowing down your gearbox though. Maybe the gears are too tight and don't spin freely. I know they're the Modify modular set, but who knows with a CYMA gearbox shell. They're not known for good tolerances. Perhaps the sector gear is "digging in" to you piston too much, causing the extra resistance and the wear, again due to poor tolerances of the shell. Hard to say, really..
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