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-   -   KWA MP7 Double feeding like a mofo (https://airsoftcanada.com/showthread.php?t=139459)

djKail April 20th, 2012 17:08

KWA MP7 Double feeding like a mofo
 
Was really excited to field this tomorrow, however after obtaining my new silencer the gun seems to be acting up.

For every 10 shots I load into any of my three magazines the gun double feeds 2 - 3 times. I am using propane, and King Arms 0.25 Bios. Any ideas?

ShelledPants April 20th, 2012 17:13

Did the problem start when you added the silencer?

If so, it's possible it's not a double feed, but the bb is hitting the inside of the silencer and cracking in half. It would not be the first time I've seen this.

djKail April 20th, 2012 17:42

Actually it did but I think it happened this way by chance. I have been testing it without the silencer or suppressor with the same results. Everything is brand new as well, so it can't be the feed lips on the magazines. I also removed the bolt for cleaning and lubing but to no avail. I can understand a double feed now and again, but 3 out of 10 shots seems pretty bad

ShelledPants April 20th, 2012 17:45

Quote:

Originally Posted by djKail (Post 1642028)
Actually it did but I think it happened this way by chance. I have been testing it without the silencer or suppressor with the same results. Everything is brand new as well, so it can't be the feed lips on the magazines. I also removed the bolt for cleaning and lubing but to no avail. I can understand a double feed now and again, but 3 out of 10 shots seems pretty bad

I want you to load 10 BBs (not more) into the magazine, and see how many double feed. I have a theory. Repeat this a couple of times if it doesn't double feed (I have a feeling it wont). *Sometimes when a magazine is loaded to the max with BB's (like 60 rounds in a 40 round magazine...) the pressure from the magazine spring will push bb's very quickly into the chamber before the nozzle can block them off. Which, because the gun is designed to feed a full magazine, means the nozzle isn't returning to battery fast enough ... which says a lot because the MP7 is really fast firing.

djKail April 20th, 2012 17:53

Hey, actually that is how I was counting. I was loading the Magazines with only 10 rounds. I would then count the number of shots before the bolt would lock. I would get on average 7 - 8 before the bolt would lock.

Could it be the BBs? I have never had an issue with King Arm Bios in my WE SCAR?

ShelledPants April 20th, 2012 18:03

Yep. Try that too. BBBastards are a good choice.

Crunchmeister April 20th, 2012 18:34

I suspect BBs are your issue. Could be wrong, but bios often cause issues.

HeadlessChicken April 20th, 2012 18:37

I was about to suggest trying BBBs, I have the same MP7 and never had issues with them but did with other brands.

Danke April 20th, 2012 18:51

On the MP7 hopup rubber swells up from silicone oil.

The fix is to change it out.

Then use less oil when lubing your mags and don't apply it to the rubber.

djKail April 20th, 2012 19:49

Quote:

Originally Posted by Danke (Post 1642066)
On the MP7 hopup rubber swells up from silicone oil.

The fix is to change it out.

Then use less oil when lubing your mags and don't apply it to the rubber.

I did a bunch of research before purchasing the gun. I am aware of this issue and only put one drop of oil on my propane tank before installing the nozzle. I highly doubt my bucking is swelling when I have only put 4 or 5 magazines through the gun. Would that cause double feeding anyways? a BB always fires, none ever get stuck in the barrel, just double fed for some reason.

I am going to try some BB Bastards tomorrow and hope it solves the problem.

Summers1000 April 20th, 2012 19:58

Quote:

Originally Posted by djKail (Post 1642095)
I did a bunch of research before purchasing the gun. I am aware of this issue and only put one drop of oil on my propane tank before installing the nozzle. I highly doubt my bucking is swelling when I have only put 4 or 5 magazines through the gun. Would that cause double feeding anyways? a BB always fires, none ever get stuck in the barrel, just double fed for some reason.

I am going to try some BB Bastards tomorrow and hope it solves the problem.

Do you do this everytime you load up a mag? Because with the MP7 (and some other KWA guns) you tend to not have to oil the propane for about 7-10 refills, rather than the traditional every couple of mags.

djKail April 20th, 2012 20:01

No, I was planning on placing one drop ever 8 - 10 Magazine fills?

Another thing I thought of...is could the magazine being low on gas cause this issue? I can get a few reloads on one fill. Maybe I should charge the magazine fully with propane after each reload?

Thanks for the tips and information. Really great community here. Appreciate it!

Fuzzy April 20th, 2012 20:09

Check the oring on the nozzle. If it is dry, the nozzle may not be retracting into the bolt carrier properly. It could cause a misalignment of the nozzle when the bolt carrier returns to battery.

Danke April 20th, 2012 20:28

Quote:

Originally Posted by djKail (Post 1642095)
I did a bunch of research before purchasing the gun. I am aware of this issue and only put one drop of oil on my propane tank before installing the nozzle. I highly doubt my bucking is swelling when I have only put 4 or 5 magazines through the gun. Would that cause double feeding anyways? a BB always fires, none ever get stuck in the barrel, just double fed for some reason.

I am going to try some BB Bastards tomorrow and hope it solves the problem.

Most likely the action is cycling but the BB is not firing. When you get a few BBs jammed in the chamber one will be kicked out of the muzzle when another feeds.

Have you wound your hopup all the way off?

In warm weather you can get a few mags from each fill. Are you sure the magazine is fully charged with gas?

djKail April 20th, 2012 21:37

Yes, The hop up is dialed all the way off. Because I was running out of things to do I dialed it up by a few notches but it has no effect. I am pretty sure the Mags are filled all the way as I am pretty familiar with GBB guns.

Again, the gun shoots a BB every time I pull the trigger. Nothing is getting stuck in the barrel nor is the nozzle failing to chamber a BB. All that seems to be happening from my oobservations and testing is the rounds are being double fed 2-3 times for every 10 rounds fired.

Danke April 21st, 2012 00:09

Anyone you know with the same piece?

I'd swap mags/guns and see where the problem crops up again.

S_Okita April 21st, 2012 22:21

could he have possibly damaged the finger on the loading nozzle that pushes the bb from the lips of the mag to the chamber?? the finger on my kwa ns2 m11 broke (common design flaw) but it did the same thing (irradic feeding) before it broke off from being misaligned. I have a kwa mp7 and love it i hope u get yours working again soon.

Soren April 24th, 2012 02:47

Quote:

Originally Posted by djKail (Post 1642028)
Everything is brand new as well, so it can't be the feed lips on the magazines.


Was browsing the KWA forums the other day and remember reading some users found the edges too sharp on the feed lip from the factory and had to lightly file/debur their new magazines. Honestly can't remember the symptoms it caused but worth inspection.

djKail April 24th, 2012 08:43

Quote:

Originally Posted by Soren (Post 1643698)
Was browsing the KWA forums the other day and remember reading some users found the edges too sharp on the feed lip from the factory and had to lightly file/debur their new magazines. Honestly can't remember the symptoms it caused but worth inspection.

Interesting. I will look into this more. I am running out of options so anything helps.

djKail April 25th, 2012 21:41

believe I have found the issue causing the double feeding. However, I am unsure how to correct it. If I place 10 BBs inside the magazine and shoot them normally in semi auto 2 - 3 will double feed. I then noticed that the magazine will not free fall out of the mag-well when the magazine release is pressed. I have to manually strip the magazine while pressing down the Mag Release.

Now, If I load 10 or more BBs inside the magazine, then fire each shot in semi but strip the magazine and re-insert after each shot I do not get any misfeeding BBs.

This leads me to believe that due to the recoil of firing the gun, the magazine is loosing its seated position and hence causing BBs to double feed. So whenever the gun is double feeding I have to manually remove the magazine as it does not free fall out. This only happens after firing the gun however, as I can insert and eject the magazine normally if I do not fire more than a couple rounds. I believe the slight recoil is making the magazine loose alignment.

What can I do to remedy this? If I try and wiggle the magazine while it is in the gun it only moves a slight bit side to side. Nothing more than any other GBB gun I own.


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