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).