MP7 not firing gels

Upgraded the spring in my V4 MP7 and it was running like a dream on 11.1V for a few hundred shots (270fps!)

Loaded a new mag and it wouldn’t feed and fire. Mag prime still works fine.

Pulled it apart, everything looked fine. I figured it was the anti- reverse latch. Took the oportunity to fix the absolutely hopeless seal it had with a brown O-Ring a Gen 8 cylinder head and nozzle I had laying around which looks to be the identical size.

Put it all back together and everything appears to be working fine, can even feel heaps of air coming out of the barrel, but it still won’t fire a single gel.

Any advice?

Tappet plate return spring all good?

Yeah it’s fine. was hoping that was gonna be the problem.

Did you try turning it upside down? See if the gels feed with gravity?
Can you see the nozzle moving? Is it moving far enough?

Is the wire polarity (negative positive) the correct way around? Red right (close to barrel side) black left (stock side) awesome mp7 bro I have had shit luck with mp7 in past so much I sold it haha. Get some metal gears and a upgraded motor ull be laughing, mp7 is a little beast.

Also side note, would buy some spare diodes just incase, the stock one won’t last long. Try not to mag dump with haha


As Random says, the mag motor may be running backwards…

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Thanks for all the responses.

Turns out it was just an issue with the drum mag. Swapped mags and away it went. The drum motor was making plenty of noise when priming which is why I didn’t h think of that right away.

I gotta say, I’m loving this little blaster. With a 1.28 unequal spring in it I saw 280fps on the chrono. ROF dropped from 17 to 14rps but it’s still quick enough for me

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Made the mistake of putting bigger spring in again today. Bye bye motor. Starting smoking right away.

Do I just buy a replacement gearbox to drop in? Or can I buy a high torque motor that will fit?

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Honestly would invest in a better motor and metal gears or u will chase your tail over and over Again. Really need that bigger motor to handle spring and metal gears so u don’t strip the little teeth on new powerful motor.

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Thanks, I’ve been searching for a motor upgrade but not having much luck. They use a little 370 motor I believe

The MP7’s really don’t handle bigger spings very well at all.
Best to go very conservative on the spring and spend time getting everything else tuned well, you should be able to get a stock v3 or v4 to around 250 and maybe 280 fps if you get everything sealed and working well with a nice barrel.