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I have also counted my shots and I can't get a full mag out of a single CO2 bulb at the moment, I really hope that these issues are related. The CO2 nozzle is supposed to be a 350-380 configuration so if anyone has a working CO2 rifle using this set-up let me know. I have tried branded with lube and no name without lube CO2 bulbs and they both act exactly the same.

Make sure the hole in part 112 (valve housing) that the CO2 passes thorugh is aligned centrally so that outlet on the mag lines up with it perfectly. My part 112 was loose and when the holes didnlt line up I was getting less than a mag out of each CO2 bulb - now I'm getting 2 mags worth. (See page 285 - mine and Nazios posts).

 

Not sure why this affects the gas consumption as surely the same amount of gas is being released from the mag each hammer strike? You'd think it would only affect the amount of CO2 being put down the barrel! Or have I completely misunderstood things??!!

 

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Make sure the hole in part 112 (valve housing) that the CO2 passes thorugh is aligned centrally so that outlet on the mag lines up with it perfectly. My part 112 was loose and when the holes didnlt line up I was getting less than a mag out of each CO2 bulb - now I'm getting 2 mags worth. (See page 285 - mine and Nazios posts).

 

Not sure why this affects the gas consumption as surely the same amount of gas is being released from the mag each hammer strike? You'd think it would only affect the amount of CO2 being put down the barrel! Or have I completely misunderstood things??!!

 

After a quick double check on part #112 it is secure and in the correct position.

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After a quick double check on part #112 it is secure and in the correct position.

Not sure what else it could be. A guy on the SCAR thread is getting 3 mags worth out of 1 CO2 bulb - isn't that supposed to have the same internals? Wonder why the inconsistency between units?

 

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After a quick double check on part #112 it is secure and in the correct position.

 

Well let me break down the problem as best I can which is usually how I solve things.

 

Assumptions:

-Gun is not getting very many shots per mag

-Mag is not leaking

-Gun does not crono very high

-O ring seals are good

 

So the gas is going "somewhere" just not forward, If the seal between the mag and bolt was bad, it would take more gas to start the blowback and reset the hammer, which might give you that behavior.

 

Or it could be the bolt itself binding or leaking gas, causing more to be required to blow it back and reset the hammer, it could be anything from a bad seal, to the nozzle not sealing all the way forward, to that plastic spacer rubbing on something and slowing the bolt down.

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Well let me break down the problem as best I can which is usually how I solve things.

 

Assumptions:

-Gun is not getting very many shots per mag

-Mag is not leaking

-Gun does not crono very high

-O ring seals are good

 

So the gas is going "somewhere" just not forward, If the seal between the mag and bolt was bad, it would take more gas to start the blowback and reset the hammer, which might give you that behavior.

 

Or it could be the bolt itself binding or leaking gas, causing more to be required to blow it back and reset the hammer, it could be anything from a bad seal, to the nozzle not sealing all the way forward, to that plastic spacer rubbing on something and slowing the bolt down.

 

Just checked everything I can think of and performed some more tests.

 

1 CO2 bulb managed to shoot 28 rounds

All rounds were fired with semi selected, around 12 trigger pulls resulted in double/triple shot bursts. It's difficult to know if all these resulted in a round being chambered and fired.

Both mags are operating in the same way and don't have any leaks, suggesting the fault is in the gun.

Chrono of a full mag started mid 440fps and ended at 328fps going down over the course of the magazine, some readings failed. I don't consider this consistent or useable.

The front o-ring seal on the CO2 nozzle is pretty ragged to be honest, shame I can't get any replacements locally at the moment. #122 is fine and all other seals appear fine.

Mags seat into #112 correctly and the seal is solid and square on.

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Are you certain your valve knocker doesn't get stuck? This happening on a GBB handgun usually comes out with half the gas efficiency which is why it comes to mind. It could be that your knocker gets stuck forwards, lets loose a couple or so rounds with the gas continuously purging when it shouldn't, wastes your gas until a third or so shot jolts it lose and closes your valve again.

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Are you certain your valve knocker doesn't get stuck? This happening on a GBB handgun usually comes out with half the gas efficiency which is why it comes to mind. It could be that your knocker gets stuck forwards, lets loose a couple or so rounds with the gas continuously purging when it shouldn't, wastes your gas until a third or so shot jolts it lose and closes your valve again.

 

Thanks for the suggestion I just removed and rebuilt the trigger unit again to check. Safe, semi and auto modes are working exactly as they should including the valve knocker. Tried another mag after rebuild, no change.

 

For reference my rifle mechanical specification is currently as follows:

 

WE M4 GBB AFC Custom v2 from Airsoft Buddy

 

Upgrades:

7075 aluminium charging handle

LAT bearing set

TSC steel hammer

TSC steel sear

TSC steel match trigger type 1

TSC anti-rotation pin type 2

Full CO2 upgrade kit

262mm Precision chrome inner barrel with new hop-up

 

and lots of furniture changes

Edited by Marky [UE]
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pics!!

 

Oh yeah. I'm about to install the chromebarrel as well and recall the bad QC of the HU rubbers. I ordered 3 extras as well. Is there some kind of quick check to figure out which rubber is good and which isn't?

 

Don't wanna take the whole barrelsection apart several times.

 

And I'd love to see PMAG for the WE M4 and Scar. Or only modified PMAG bodies. So you could use your current magazine internals.

Edited by somegirls
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If you weren't a million miles away i'd take a look at it just for the learning experience.

 

If you play with the trigger mech manually with your finger, holding down the trigger and moving the hammer around in semi, can you reproduce the doubleshot burst?

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pics!!

 

Oh yeah. I'm about to install the chromebarrel as well and recall the bad QC of the HU rubbers. I ordered 3 extras as well. Is there some kind of quick check to figure out which rubber is good and which isn't?

 

Don't wanna take the whole barrelsection apart several times.

 

And I'd love to see PMAG for the WE M4 and Scar. Or only modified PMAG bodies. So you could use your current magazine internals.

 

I will get some pics done when I don't feel like throwing in the towel... getting mighty close at the moment :headbutt:

 

Double check Ottos post on page #239 regarding rubber selection. That's the only info I can recall.

 

I have taken the barrel apart lots of times now and it's a real pain in the neck.

 

A PMAG or a PMAG outer would be really nice.

Edited by Marky [UE]
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If you weren't a million miles away i'd take a look at it just for the learning experience.

 

If you play with the trigger mech manually with your finger, holding down the trigger and moving the hammer around in semi, can you reproduce the doubleshot burst?

 

Yeah I wish I had a WE owner nearby with some fresh eyes.

 

I spent about twenty minutes staring at the trigger unit doing just that earlier but alas no cigar.

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I spent about twenty minutes staring at the trigger unit doing just that earlier but alas no cigar.

 

Only thing I can suggest at this point is going back to all stock internal parts except the c02 bolt and seeing if you have the same issue and then add them one at a time.

 

Do you get garbage performance on propane too?

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Only thing I can suggest at this point is going back to all stock internal parts except the c02 bolt and seeing if you have the same issue and then add them one at a time.

 

Do you get garbage performance on propane too?

 

I upgraded the stock trigger parts after the problem started to occur in an attempt to resolve the issue. As you say not much left to try so maybe a full stock rebuild is in order. I have run out of green/propane gas so I can't confirm how that works at the moment.

Edited by Marky [UE]
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Just did some test shooting in back garden. 1 x CO2 capsule can empty app 1.5 magazine, didnt count bb's is more or less. Happened 1 double burst on 2.5 magz of co2. On propane nothing strange - blowback, cycling, everything looks normal. On co2, first 2 shoots loud, i can feel rifle shoots with its full strengh and then fps drops rapidly blowback is very weak rifle is not working properly. Quick egzamine of nozzle, widest o-ring is harmed, also nozzle head looks like it was harmed by something.

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Thats the one. Nope. Either charging by cocking handle with mag in, or make one empty shot when unlocking trigger from safe position. But still something harms o-ring. On last event the same o-ring was removed from its original position while shooting. Not sure what it may be, might guide rod loose and nozzle is not enetring valve housing properly. Now i see mags are falling out of rifle while shooting. Another issue to sort.

Edited by Nazio
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I was thinking what might have damaged the end of your nozzle and it could because you have the nozzle/bolt forward when loading a full mag.

 

From the wiki 'best practice' page ( http://wem4guide.wikidot.com/best-practices ) ....

 

Charge That Handle!

If you have owned any GBB submachine guns in the past, you will know that pulling the bolt back should always precede trying to load a full magazine.

 

If you don't charge the bolt (pull the bolt back) the loading muzzle will be right where the bb stack wants to be.

 

In the past, on GBB sub machine guns like the KWA M11A1 (or TMP) trying to jam a fully loaded mag would instantly damage the thin aluminum loading muzzle.

 

If your magazine is TOTALLY full (not one more bb can fit in the mag), the bb stack has zero give or "spring". When it contacts the loading muzzle, it is two solid parts coming together. Not good.

 

What's worse in this scenario, is when the operator can't get the mag to lock in, he slams it from the bottom. Wrong! You are damaging the loading muzzle.

 

The WE M4 loading muzzle is quite robust (solid brass). But the threads have given out on a couple of rifles on the forums. I suspect that it is likely the cause of slamming a loaded magazine in the well, with the bolt/loading muzzle forward.

 

The solution?

 

Simply rack the bolt before every load. Use the "bolt stop", that's what it is there for.

 

Another precaution is to load the magazines slightly less than full. This will ensure a little spring left in the bb stack. This give would allow the operator to load a full mag without the bolt being pulled back (Should he/she forget).

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i had the same problem, the wide o-ring on the co2 nozel would sometimes come off and the small one has a bit of damage to it. I have lubed it up and it dosent seam to do it now but it sometimes dosent seam to shoot at full power. Some shots i would get a real kick and then one or two would be realy weak and then back up to full power again. Will do it on full auto too.

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