Hay, haw much would it slow dawn a classic army m15a4 with a 8.4v 1400 mah mini battery buy putting in a PDI 150 or 170? like would it be extremely slow and i would have to upgrade my whole machbox or would it just slow it dawn a touch?
I would really like to reach 400FPS without too much expense and if you have any suggestions on what else i could do please feel free to share them.


thank you,

Prometheus MS110SP should be all you need to get it to at 360-395fps with a slight loss in rate of fire. It shouldn't be too bad though, but if you have the money to spare, I'd recommend torque up gears as well to increase the life of your motor.

thanks, any suggestion on a good hight torque gear set?

You can't go wrong with Systema or Prometheus. You don't need to go beyond one torque level above standard ratio for that spring. High torque is added expense, and reduced rate of fire. Sure, your battery and motor will last forever, but on the field, sometimes that compromise isn't worth it.

Isn't 395 above most field limits?

For an AEG it's really pushing it.

Staypufft? You should also check out about the legal ownership of AEG in Canada and playing age in most of Ontario before dropping cash into that gun.

At 17, you have not long to wait to be legal, but until then it's still an issue you have to resolve.

For the gun, I'd try to get it working perfectly at about 340-350fps. Then it will last a long time.

That depends on what field, but generally for outdoor games run by ASC hosts, 395 does not break the limits. 400fps is usually the limit, but like Greylocks always says, 400 is a LIMIT, not a goal. There isn't much performance difference between say 380fps and 395fps, but some people just want to squeeze out every last drop of performance.

my G3 has a PDI 120 (around 370 fps) yeah probably a mispackaged spring, but even with that, if i switch to a mini battery it often jams in semi auto with the piston all the way back because the battery cant force the motor enough to drive it back that extra 4 or 5mm, you'll need torque up gears.
FYI between my friends M41 (310fps) and my G3(370fps) theres a difference of about 250 rounds per minute. both on large batteries, standard gears

or a bigger battery...

I'll add the bit, seriously get the PDI springs out of your head. Go with Illusion's recommendation, Prometheus.