WA system GBBr stoppages

[TheFull9]

I did actually post this question up in the AGM topic under gas rifle reviews, but obviously not all that many people look there and it was around a year ago now, so I'm hoping the proliferation and experience gained by various people around will mean someone might have an idea of how to go about sorting this.

 

I'll go straight in to the videos I made to show case the problem:

 

http://www.youtube.com/watch?v=wZmmPi_O5f0

 

http://www.youtube.com/watch?v=_3wQD-Lf-dw&feature=related

 

In terms of the make up of the weapon, it started out as an AGM, but there's not a huge amount of that left. The receivers and lower internals are stock (for now, G&P replacements on the way for hammer, sear etc), as is the charging handle. RA-Tech steel carrier and aluminium NPAS nozzle, RA-Tech bolt catch, Prime AEG/Rear adjust hop unit, Pro-Arms outer barrel (if that makes any difference), using GHK magazines and madbull match grade 0.2s.

 

I know for a fact that the problem is cause by the magazine feeding 2 BBs at a time when should only feed 1. The first goes in to the hop as it should, but the second ends up somewhere between the front of the nozzle and the inside of the upper receiver near the front. This means the the nozzle isn't correctly aligned with the top of the magazine, it's sitting slightly too far back (about 6mm funnily enough), so the whole bolt assembly fails to recoil upon pulling the trigger, meaning the valve knocker is left pushing on the mag's release valve and it simply vents all the gas in the reservoir. I've tried all my GHK mags, same issue, as with the AGM mag that came with the gun, also different types of BB make little difference, some seem to alleviate the problem very slightly, but not fully, and that may just be random chance.

 

If anyone has experienced anything similar to this, or has any suggestions about alterations or new parts to buy to fix the issue, then all information is appreciated.

[UrPeaceKeeper]

I did actually post this question up in the AGM topic under gas rifle reviews, but obviously not all that many people look there and it was around a year ago now, so I'm hoping the proliferation and experience gained by various people around will mean someone might have an idea of how to go about sorting this.

 

I'll go straight in to the videos I made to show case the problem:

 

 

 

In terms of the make up of the weapon, it started out as an AGM, but there's not a huge amount of that left. The receivers and lower internals are stock (for now, G&P replacements on the way for hammer, sear etc), as is the charging handle. RA-Tech steel carrier and aluminium NPAS nozzle, RA-Tech bolt catch, Prime AEG/Rear adjust hop unit, Pro-Arms outer barrel (if that makes any difference), using GHK magazines and madbull match grade 0.2s.

 

I know for a fact that the problem is cause by the magazine feeding 2 BBs at a time when should only feed 1. The first goes in to the hop as it should, but the second ends up somewhere between the front of the nozzle and the inside of the upper receiver near the front. This means the the nozzle isn't correctly aligned with the top of the magazine, it's sitting slightly too far back (about 6mm funnily enough), so the whole bolt assembly fails to recoil upon pulling the trigger, meaning the valve knocker is left pushing on the mag's release valve and it simply vents all the gas in the reservoir. I've tried all my GHK mags, same issue, as with the AGM mag that came with the gun, also different types of BB make little difference, some seem to alleviate the problem very slightly, but not fully, and that may just be random chance.

 

If anyone has experienced anything similar to this, or has any suggestions about alterations or new parts to buy to fix the issue, then all information is appreciated.

 

What sidelock plate are you using on the RA Tech bolt? Is it worn? That will cause nozzle misalignment. Also what BB's have you tried? Have you replaced the mag catch? The only way to get a double feed like that is to have a mag that sits high, or BB's that are too small (Excels) and multiple can slip through during recoil or the part that pushes the BB's from the mag up is grabbing multiples at a time.

 

At least, thats my limited experience with my G&P WOC talking. You may wish to go over to GasGuns.info and ask there too!

[L4byr1nth]

Bolt's not returning correctly. Sure it's fully lubed?

 

Had this problem recently on my WE SCAR (the SCAR system is very similar to a WA-type system in that the whole bolt carrier recoils). Bolt doesn't return all the way, next trigger pull vents all the gas in the mag. Mine was because the nozzle was stuck in the cylinder - not enough lube.

 

Seriously, you want to lube the working parts with silicone grease, not just silicone spray(I only use silicone spray on the trigger mech). Make sure the grease you use is safe for use with rubber.

 

As for double feeding/general jamming, turn the HOP down? Better quality BB's?

 

Ben.

[Luis21]

Make sure that every BB is getting shot out every time that you pull the trigger. Sometimes too many BBs stack in those Prime-style rear adjust chambers to the point of jamming and BB dribbling.

 

Also, what recoil spring are you using?

 

 

-Luis

[tinydata]

Sounds like the shots fired are hitting the target with some force, so I'll rule out dribbling/pissing shots

 

I ran GHK mags in my AGM, first WOC, and possibly my Ino

 

The main problem with them is that they are so tight. They sometimes snag the bolt carrier, causing jams and vents. In your case though, it seems to be cycling fine for a while.

 

I can really only think of two things at this point.

 

A. The GHK mag lips got spread too far/weakened by repeated abuse from the loading nozzle. This happened to both my GHK mags. Only solid fix for this is new mag lips, but you might get away with cramming a piece of plastic between the feed lips and mag shell to squeeze them back together.

 

B. The mag lips/BB channel are too slippery due to the silicone in green gas. This has happened to me also, where the mag lips can't exert enough pressure to hold the BBs in. Disassemble the mag and thoroughly wipe anything the BB touches

 

 

Other issues might be a worn loading ramp, my Inokatsu came with a defective one and jammed all the time.

 

If you have a good camera, slow down the video when taking the shots from an angle like this: http://www.youtube.com/watch?v=13xDBg3-ENQ

It could reveal something

 

If GHK mags prove to be too much trouble, my G&P mags have given me nothing but great results. For $45 apiece they're good stuff.

 

Tell us how it works, good luck man!

[TheFull9]

Thank you for all the replies so far guys.

 

What sidelock plate are you using on the RA Tech bolt? Is it worn? That will cause nozzle misalignment. Also what BB's have you tried? Have you replaced the mag catch? The only way to get a double feed like that is to have a mag that sits high, or BB's that are too small (Excels) and multiple can slip through during recoil or the part that pushes the BB's from the mag up is grabbing multiples at a time.

 

At least, thats my limited experience with my G&P WOC talking. You may wish to go over to GasGuns.info and ask there too!

It's RA-T's own side lock plate as well, I did have an issue with it not fitting flush at one point but that's all sorted now, no wear on it far as I know. I've tried Excel and Madbull 0.2s, I've got some KSC 0.25s on the way since I've set it up to shoot about 350FPS on the NPAS. Mag catch is the stock one for now, but the G&P parts set on the way will have a replacement for that. The mag sitting high/too small BBs had occured to me as well actually, I'll go over and copy my post on to GGI, good idea.

 

Bolt's not returning correctly. Sure it's fully lubed?

 

Had this problem recently on my WE SCAR (the SCAR system is very similar to a WA-type system in that the whole bolt carrier recoils). Bolt doesn't return all the way, next trigger pull vents all the gas in the mag. Mine was because the nozzle was stuck in the cylinder - not enough lube.

 

Seriously, you want to lube the working parts with silicone grease, not just silicone spray(I only use silicone spray on the trigger mech). Make sure the grease you use is safe for use with rubber.

 

As for double feeding/general jamming, turn the HOP down? Better quality BB's?

 

Ben.

So far I've actually only been using a spray, which obviously is not viscous in the slightest, but I do have some nice Kick-*albatross* silicone grease that's good and thick so I'll get some of that on the nozzle/bolt carrier. I do know it's definitely a BB getting stuck at the front, because I've found them there whenever I lock back the bolt after the problem happening. In fact if you very closely watch the end of the second video you can see the culprit in question drop down as I tip it out of the ejection opening. Actually I've done a lot of heavy filing and wet n' dry work inside the entire receiver set since it was full of the thick nasty AGM paint; the mag housing was too tight for the GHK mags so the ribs inside it got filed down a fair bit and then that area, as well as the entire inside of the upper, were smoothed down with medium then fine grit WnD so it's all super shiny and very smooth inside there now.

 

I may well look in to the hop rubber, as it's impossible to tell right now if the 'extra' BB is just dropping straight away loosely in to the receiver or getting fed up to the hop unit and falling off the feed ramp/bouncing back out, or perhaps getting knocked out when the bolt is recoiling as opposed to going forward. I've got a Madbull red bucking in there at the moment which is pretty thick, so perhaps I'll try swapping that for a more standard type made of thinner material.

 

Make sure that every BB is getting shot out every time that you pull the trigger. Sometimes too many BBs stack in those Prime-style rear adjust chambers to the point of jamming and BB dribbling.

 

Also, what recoil spring are you using?

 

-Luis

It's been a while since I fired this thing so I'm only about 97-98% on this, but I'm pretty certain a BB was being fired out of the barrel on every single shot. Recoil spring is the stock one right now, cheap enough to buy a better one but far as I've read the AGM ones are alright which is why I've left it until now.

 

Sounds like the shots fired are hitting the target with some force, so I'll rule out dribbling/pissing shots

 

I ran GHK mags in my AGM, first WOC, and possibly my Ino

 

The main problem with them is that they are so tight. They sometimes snag the bolt carrier, causing jams and vents. In your case though, it seems to be cycling fine for a while.

 

I can really only think of two things at this point.

 

A. The GHK mag lips got spread too far/weakened by repeated abuse from the loading nozzle. This happened to both my GHK mags. Only solid fix for this is new mag lips, but you might get away with cramming a piece of plastic between the feed lips and mag shell to squeeze them back together.

 

B. The mag lips/BB channel are too slippery due to the silicone in green gas. This has happened to me also, where the mag lips can't exert enough pressure to hold the BBs in. Disassemble the mag and thoroughly wipe anything the BB touches

 

 

Other issues might be a worn loading ramp, my Inokatsu came with a defective one and jammed all the time.

 

If you have a good camera, slow down the video when taking the shots from an angle like this: http://www.youtube.com/watch?v=13xDBg3-ENQ

It could reveal something

 

If GHK mags prove to be too much trouble, my G&P mags have given me nothing but great results. For $45 apiece they're good stuff.

 

Tell us how it works, good luck man!

Yep, definitely no FPS issues with the fired BBs, as you can see from the videos the chances of the actual problem happening are very random. Sometimes it will go through the whole mag no problem, sometimes it'll jam up like that on every single mag part of the way in. I wouldn't think the mag lips would actually be worn too much because the mags themselves really haven't seen very much use to be honest, looking at the they do appear to be fine but it certainly might make sense that they've been split/pushed apart by the nozzle, I'll be getting some replacements once they're released at any rate. I shall give suggestions A and B a try at any rate that's for sure.

 

Loading ramp I'm pretty sure is fine, although unfortunately the AGM upper has that part moulded in to it rather than being a separate piece unfortunately so if it is knackered I don't think there's anything I can do about it. Could the cocking handle possibly be anything to do with it? I'm still on the stock one, but perhaps an upgraded one which the key on top of the bolt carrier fits more tightly in to will remove some slop, which would keep the loading key on the bottom of the nozzle in slightly better alignment? How about the actual buffer itself, is keeping the stock AGM plastic one likely to cause any problems related to all this?

 

Will try and get some video recording done soon as possible, not sure if I've got a video camera that records at decent enough FPS but maybe my new phone will have some sort of feature for it. New mags are the main things I'm looking in to right now, since pro-win and chinese ones are out of stock everywhere it looks like it's a decision between Bomber, G&P and KA. Far as I can tell they're all fairly similar, G&P and bomber being the exact same price and design, KA slightly cheaper so I'm not leaning towards those. Anyone have any thoughts?

[tinydata]

My AGM went through a couple thousand rounds before the trigger pack failed and I moved on, so maybe the feed ramp is fine.

 

I've never heard of a charging handle screwing up the firing process like that. The bolt carrier should mostly stay aligned with the walls of the receiver. If it is, I recommend the 5KU SPR style charging handle. I've had one in each of my WOCs and it has never failed or snagged. Great product for $20

 

The buffer might be deformed but I doubt it really would affect the cycle that much. Mine held up pretty well. Either way, it travels linearly and is guided by the tube

 

Here's an easy way to diagnose whether your magazine is having issues. Load it up with 40 BBs. If the top BB is not snug in either the left or right corner of the mag lips, and instead it is in the middle of the channel, that means your mag lips are spread too far. If this happens, a good jolt (like hitting the magazine, or the blowback) will cause the BB to slip out. Also, because its not being properly contacted by the square loading key, it may be chambered too high and get stuck in between the nozzle tip and barrel extension. (it looks like that is happening in your video) Double feeds can also occur this way.

 

As for magazine choices, pro-win mag lips bend and break pretty easily, with no replacements. Bomber didn't work well for me, sprung a leak after 70 or so shots and refused to be sealed even with an o-ring replacement.

I have one Gen I G&P mag, and it works great, but some people report issues. As for the Gen II magazines, I ordered four and all four hold gas and feed perfectly. For $45 you can't beat them.

 

I'd say order one or two and see how it works. If they do, problem solved lol

If not, you just got some solid mags

[TheFull9]

Well, I think either way you're right in what you say, if it's going to be anything it'll be the magazines. Had a look around and Redwolf's write up of the Bombers reckons they should have O-Ring upgrades if you want to run them with propane, so I'll get 2 of the G&Ps and see what they do. Worst case scenario they don't have any effect, but I'll be getting a WOC or 2 at some point any way so there's no risk of wasting the money.

[tinydata]

Yeah, the key with WOCs is "KISS"

 

Keep it simple, stupid lol

 

Plastic nozzles work best in them (with alu tips if you wish)...trust me I've spent an obnoxious amount of money on alu nozzles. They're just not worth the trouble.

 

I'll be gone for three weeks so no more help, but good luck!

[TheFull9]

I'll bear that in mind. Cheers for all help mate, I'll post up once I've done some more testing and fingers crossed it'll all be shooting nicely.