KWA/Umarex MP7 - Issues/Attachments

[RabidNinja64]

Godnoes where to start, but to save time; Yes, it is a phenomenal gun for a discounted First-hand GBB SMG, Yes it does have it's current issues which i'll need some guidance with and Yes I may have a match coming up soon, and my birthday falls on the 24th which also gives me a £50 spending leeway, which is more than likely going to toward attachments and gas for my mp7. Onto the first order of buisness......


Got myself the Navy version; extra rail on the bottom, giving me more customisation

ISSUES
A few months back I had an issue with my MP7 concerning the bolt release. that has now been fixed, but now more issues have risen.

To start, the bolt will occassionally lock back when the charging handle is pulled, and when the release is pressed, the bolt will move half an inch forward and stay there, giving me 5 mins to pull the handle and release until its back to normal. At one point, the bolt was even jammed when i attempted the first pull of the charging handle! As a beginner airsoft, this worries me, but not as much as the next issue.

Double feeding and/or not firing. However, Double feeding was a past issue, because now its along the lines of quadruple feeding and puking BB's all over the bolt and chamber. for the technicals, I use 0.20 gram BB's and Green gas(See attachments for specific gas used), have disassembled it ONCE and that's when the problems appeared.


Here's the type of green gas that I used prior to the issues, if it helps.

My only thoughts on fixing bolt issue is A) Invest in a low-power CQB bolt ASAP. B.)Oil up the bolt linings to ensure it's running smoothly C) Disassemble the gun again and double-check everything's where it should be.

As for the quadruple feed; A) Invest in another magazine B.) Assume the magazine spring and/or feeding lip is damaged, creating eiter a bigger feed hole in the mag or is pushing bb's up too fast, and attempt to find a fix for these issues. C.) Bucking has swelled within the gun and needs to be replaced.

Hopefully someone can help and is an experienced airsoft engineer

Moving onto my favourite topic......

ATTACHMENTS

As mentioned above, a low-power bolt is on my priority list, but im unsure where i can buy one as i'd rather not fork out more than £20-25 for one overseas, that's if the rumours of KWA discontinuing the MP7 are true. Even then, I've heard mixed reviews on the NPAS valve kit, so im skeptical on that.



Here's my baby in it's glory along with the G18C. Pretty sexy with it's attachments, but i feel that it could do with more. Naturally, im stuck with choosing a specific type of laser, so im tempted to get a green PEQ-15 laser replica; their big but not clunky, remain flat and parallel to the gun and gives me more of a meaner look, in my personal opinion. I'm also thinking of getting a flashlight, possibly a QD suppressor.....or a tank buster barrel, which will need a 16mm to 14mm adapter, to my knowledge.

Overall, opinions will be most appreciated, and personal reviews and pictures will be even more

TL;DR - Bolt's jamming and double feeding, need fixes. recommended attachments also requested.

[straffham]

I can only comment generally as I've not worked on the MP7, however you say problems only started it when you disassembled it, so what did you disassemble? Just take the bolt out? If so did you clean all the grease off it? Gas SMG's do need to be kept well lubricated in the right places to function properly, I have a CO2 mini Uzi, personally I find a little general purpose grease works best on metal to metal rails/bolts (rather than airsoft specific grease), and I never use silicon oil spray on these parts as its simply too light a formula (though silicon grease is great on gas routers, internal gas blowback parts etc). It does involve more cleaning/regreasing after a game (which is usually recommended anyway with gas guns) but has't let me down.

As for the feed issue, does the mag sit firmly in place with no movement? The relationship between mag feed lips and the air nozzle (which usually have a protruding lug underneath to push the bb out of the mag into the hop chamber) is critical, if this lug is in anyway damaged or catches on the mag feed lips it won't feed properly, or may just jam completely.

The mag feed lips equally need checking for signs of wear caused by catching on the lug mentioned above, it SHOULDN'T happen but it can, esp if the mag has any movement in the gun. This could explain the double feeding, my guess is its the mag lips at issue, though to prove this you'd need to try a new mag for comparison. New mag lips are available for most common gas guns too, though you may need to search around for them (WE are supposed to have good support for parts though I'm unsure as I don't have any).

I doubt the hop is the issue as multiple bbs have already left the mag by sound of it, but a simple way of testing if there is a problem would be to try turning the hop right off, firing a few shots, then gradually applying more hop to see if the problem gets worse or better, does the multi feed problem occur on semi or full auto, or both?

Also try different gases if you can? Failing that If the NPAS kit isn't available another route is to modify or replace the floating valve in the blowback housing, basically if the gun is too hot the floating valve needs the long stem beefing up a little with plastic filler to restrict flow to the bb (very much trial and error, and don't do anything irreversible), or you may find an aftermarket blowback valve part to do the same job from somewhere like Firesupport.

Sorry its not specific but hopefully this might help you find the problem.

[RabidNinja64]

I can only comment generally as I've not worked on the MP7, however you say problems only started it when you disassembled it, so what did you disassemble? Just take the bolt out? If so did you clean all the grease off it? Gas SMG's do need to be kept well lubricated in the right places to function properly, I have a CO2 mini Uzi, personally I find a little general purpose grease works best on metal to metal rails/bolts (rather than airsoft specific grease), and I never use silicon oil spray on these parts as its simply too light a formula (though silicon grease is great on gas routers, internal gas blowback parts etc). It does involve more cleaning/regreasing after a game (which is usually recommended anyway with gas guns) but has't let me down.

As for the feed issue, does the mag sit firmly in place with no movement? The relationship between mag feed lips and the air nozzle (which usually have a protruding lug underneath to push the bb out of the mag into the hop chamber) is critical, if this lug is in anyway damaged or catches on the mag feed lips it won't feed properly, or may just jam completely.

The mag feed lips equally need checking for signs of wear caused by catching on the lug mentioned above, it SHOULDN'T happen but it can, esp if the mag has any movement in the gun. This could explain the double feeding, my guess is its the mag lips at issue, though to prove this you'd need to try a new mag for comparison. New mag lips are available for most common gas guns too, though you may need to search around for them (WE are supposed to have good support for parts though I'm unsure as I don't have any).

I doubt the hop is the issue as multiple bbs have already left the mag by sound of it, but a simple way of testing if there is a problem would be to try turning the hop right off, firing a few shots, then gradually applying more hop to see if the problem gets worse or better, does the multi feed problem occur on semi or full auto, or both?

Also try different gases if you can? Failing that If the NPAS kit isn't available another route is to modify or replace the floating valve in the blowback housing, basically if the gun is too hot the floating valve needs the long stem beefing up a little with plastic filler to restrict flow to the bb (very much trial and error, and don't do anything irreversible), or you may find an aftermarket blowback valve part to do the same job from somewhere like Firesupport.

Sorry its not specific but hopefully this might help you find the problem.

By disassembly, yes, i removed the bolt but did NOT wipe the grease off it; First time round with lubricating prior to firing was using silicon lubricant (to my knowledge. my older brother did it for me).

 

The magazine itself is as firm as the day i bought it, and the gun has been fired numerous times using the aforementioned gas to the point it was emptied, though i do recall using a seperate gas at some point or another, if that is a possibility of an issue. The multi feed occurs on both semi and full, but even then to the point that a single trigger pull doesnt even shoot a BB, it runs straight back to multi-feeding.

 

If all else fails, ill switch out the gas, get a new magazine. if the problem persists, replace the bolt or get the NPAS kit. Failing that, someones getting an MP9........