Misfiring KWA CQR Mod2

[snown]

I have a fairly new KWA CQR Mod 2 (been in about 25 skirmishes) that has started to misfire sporadically. Every once and a while when I fire it will sound as if the magazine is empty, but if I tilt the gun forward a BB will roll out of the barrel, and if I pull the trigger again the next shot will fire just fine. When this happens sometimes the rest of the magazine will fire fine, other times it will misfire again in 10 or so shots, and yet other times it will misfire again immediately. I have not been able to determine a pattern.

My setup is:

• KWA CQR Mod2
• 7.4v 2200mAh LiPo
• KWA 120 Midcap Mags
• Bioval .25g Biodegradable BBs

I have cleaned the barrel, hop up feed tube, and took apart and cleaned each of my magazines. The issue occurs whether the battery is fully charged, or if it's been used for several games. This seems to happen most often in semi-automatic mode, it may also happen in full-auto, but I almost never play in full-auto so I don't know for sure. I pulled out the magazine immediately after a misfire to see if there was a feeding issue, and there seemed to be a BB halfway out of the magazine's feed, but then I pulled the magazine out after a normal fire and it was in the same state. If I fire the gun with the upper receiver off, and no magazine the air nozzle seems to cycle forward and push air as expected.

I'm out of ideas. Do any of you have suggestions on what I could try next to resolve this issue? It's pretty frustrating to have my gun not fire when I need it to.

Thanks in advance!

[snown]

Should I assume that with no reply my gun is broken beyond normal repair? Is there a different forum someone could suggest that I might try? Or should I just take my gun in for service?

Thanks!

[AndyC]

I had the same type of issue with my cqc mod2. Not feeding properly. I fixed this issue by replacing the KWA bucking with a madbull blue and fishbone type nub. I would check to see that your hop bucking is not misaligned or torn/defective in anyway.

[snown]

Thanks Andy! I hadn't thought of checking the hop-up bucking. I'll look into it.

[snown]

Well, I got the chance to look at the hop-up bucking, and it looked aligned, and not torn. However, I decided to disassemble the hopup, and make sure everything was where is should be. I added some silicone oil when i put it all back together, and initially I thought it was working better, but soon I started getting the same misfire issue.

Just for fun I started looking at replacement buckings and I saw the Madbull Shark bucking. I then found this image describing a problem with some traditional buckings accidentally letting BBs in the barrel when they weren't supposed to. I took my hop up off again and tested by placing a bb on the opening of the bucking, sure enough the BB just rolled right through, no real resistance at all.

Since I never performed this test before I started having this issue I'm not sure if it's normal for the BB to roll right through the bucking like that if the Hop-up unit is removed. Can anyone tell me if this is normal? Could this be the cause of my misfiring issue?

I also tried it with the hop up unit in place, and it seemed to hold the BBs a little better, but very little effort (like dropping a second BB on top of the first from about an inch up) would push the bb through the bucking opening. It seems like a magazine with any significant force coming from the spring might force a BB into the chamber?

Thanks again for all of your help!

[AndyC]

The 'skirt' on the end of the bucking should hold the BB in place. I would look at getting a better quality bucking.

[spazzticsmurff]

i would also check your magazines in another gun to make sure it is not them. i have seen many times that people thought it was their gun that was having the issue, but as soon as i popped one of my flash mags into their guns, it feed perfectly.
kwa stock gears come with an enlarged tappet cam allready and they tend to help with the longevtivity of the tappet.
you may have just cleaned and serviced them but that doesnt rule them out as the cause of the issue. find a friend with mags that you know feed properly and try them in your gun. another thing you can try is holding your mags firmly into the magwell. you could be having an issue with the feed lip in the mag well not properly engaging the catch in your mags.

[snown]

You make some good points spazzticsmurff. I'm still thinking that it's the bucking, but when I go into the store (I was going to order online, but I think a storefront will be better in this case) I'll see if they can run some rounds through it with a different mag.

The failure is so sporadic, it seems odd that it would be a mechanical issue with the mag (a relatively simple mechanism). Also when I cleaned them I took them all the way apart (pretty easy to do with the KWA 120 mags), and they looked in good shape, I checked for any burs or anything the spring or follower might be getting caught on.
If it is the mag it's weird that all 4 of my mags are failing at the same time. It's also weird that my friend who has the same gun bought at the same time and the other half of the 6 pack of mags we bought, is not having this issue with any of his magazines.

The mag lip issue was something I was aware of previously and I did try holding it in while firing, but it still misfired at times.

Anyway, like I said I'll try a different magazine when I go in, but I feel like the evidence is pointing more towards the hop-up.

[snown]

This took me a lot longer to complete than I anticipated, but I ended up buying and installing a new hop-up bucking, and it seems to have fixed the issue.

I've only had a chance to put one magazine through it, but previously it would have misfired at some point during that single mag, so I think we're in the clear.

Thanks for your help everyone.