MP7 Troubles...
 

Having a few problems with my MP7...

When using low-cap mag, I have never had a problem, and using a hi-cap mag I am usually fine; but over the last week or so the hi-cap mag has been giving me trouble. Today, I couldn't get the hi-cap to fire properly (feeding issues I think, possibly needed lube)- when shooting in full or semi.

I set the gun down, outside, and went to get some silicone oil and a rod to see of there was a jam... When I returned, the MP7 would not fire at all (full battery).
Pulling the trigger on full or semi would result in nothing, as if the battery were disconnected but physical safety was not engaged.

I figured cause to be the fuse, or loose wire. I first tried removing the battery for a bit, and then tried firing, with no luck. So I took the top rail off, revealing the fuse and location where power (to motor) connect to battery. I pushed down on the cables, which felt firmly seated, and moved the fuse slightly. Then put the battery back in, and took a shot on semi (dry fire) and was successful. After that, nothing more.

Tried the same procedure again and can't get it to fire.

Any suggestions?

it sounds to me like you have a loose wire somewhere, try checking every single connection

Loose wire? It was able to shoot once after I jiggled the fuse and put the battery back in. My guess if it wasn't fuse related, or something with the cables coming from the battery, then it is the battery itself.

It is one of those stupid mini batteries; maybe I will pick up a new one from ebay.

you may want to test things out a bit more before you go on to buy another battery. It could be your switch, wires inside the gun going to the motor, bas solder joint of the wires attached to the motor, dirty contacts for the battery/switch, etc. Tons to look for before you go out an buy a new battery :)

FYI, it seems the MP7 hicap is a worthless turd. Mine won't feed worth a darn either and I've given up on it. Just as well since hicaps suck to begin with. Get a nice box of STAR 50-round lows, 20-round reals, or MAG 100-round midcaps and you're set.

Okay, made some progress today. I think the problem is the contact between fuse and its seat. There are wires that run along side the fuse and its contact, which put pressure on the connection to keep it solid. I guess over time through vibrations the wire had worked its way up, loosening the connection. Pushing the wire back down, seems to give it a solid connection and everything works :)

Scratch that...

Found the REAL problem. Took the thing apart this aft.

One of the wires connecting to the gear box is disconnected... sloppy soldering in Japan.

Hopefully that is all that is wrong; going to solder the wire back into place and post some photos of MP7 internals for others.

Edit- Soldered wire and re-assambled the gun. This fixed the firing problem but now I have no semi-auto. Safety ats as safety, semi acts as full auto and full auto acts as it should.

make sure that the semi disconnect lever is connecting with the mechbox correctly

The MP7 is very tight and I don't know the gun that well... Any tips on how I go about doing this?

hmm i really don't know how i do it myself haha. there's a plastic arm that connects to that piece on the top of the mechbox, i just remove and replace and jiggle to get it in and connected, i find i normally can't close the whole gun if that isn't connected as the motor shim never fits.

After a lot of playing i think I've got it... :)

Please.. feel free to tell the rest of us how you fixed it.. I put in a new 6.01mm barrel. and lost my semi-auto too. cant see what I did wrong. So please... help me.

Nevermind.. fixed it.. its a pressure thing. if the mechbox isnt pushed in hard enough when your putting it back together.. it doesnt enable semi-auto. so you have to make sure you really push it in there and make sure the rest of the parts are in tight.

Sorry- didn't notice this thread, but yes. I just took the mechbox back out and re-seated it more firmly and had no trouble.

BTW- did you enjoy threading the electrical wires back through that tiny hole? Fun stuff eh :)
(I tied a thin piece of copper wire to the wires and then simply thread that through the hole..and pulled the wires through. This, after trying to guide them through with my hands for 15 minutes):cool:

lol.. I used thread.. tied it to a small allen key.. dropped it through.. and tired it on to the wires. but if you want to make it a bit easier. Take the cocking handle spring off the mp7 first and make sure the ejection port is open.. that will give you more room and a bigger hole to get it through.