WETTI/AWSS - M4/SCAR/HK416 - Technical Summary Thread

[m102404]

If you've identified a broken/mangled part...I'd suggest that you stop using it until you sort that piece out. These things are pretty tough on parts when everything is working right...when something's out of wack, you risk breaking something else.

Take a look at some of the pics I've posted...look at the damaged/crunched nozzle. I'm pretty sure that's it started off from some pretty nasty jams...and got worse with more use. To the point where it was not sealing at all. I ran it to destruction on purpose.

I'm not sure how the rifle can triple feed in full auto (or else it'd do it in semi too). Unless there is something majorly wront with your bolt/nozzle assembly and it's alignment/movement with the mag feed lips.

If you start with a clear chamber, full mag of gas and bbs, bolt forward.
- insert mag
- rack bolt all the way back, release
- remove mag
---how many BB's are in the chamber (you might need a rod to clear the barrel)? Should be one. If it's more than one you have an immediate issue with either the nozzle, the feed lips or the bolt. Repeat this test to see consistent results.

If you start with a clear chamber, full mag of gas and bbs, bolt forward.
- insert mag
- rack bolt all the way back, release
- semi auto fire 1 shot.
--shot should leave the muzzle, there should be one in the chamber (clear barrel to confirm. Repeat to confirm

If you start with a clear chamber, full mag of gas and bbs, bolt forward.
- insert mag
- rack bolt all the way back, release
- fire a short burst (ideally 2 shots...at most 4...whatever the number count how many shots)
-- did a shot come out each time?

But again...I wouldn't bother doing any of that until you get the knocker problem sorted out. If the knocker isn't hitting the main valve fully/repeatably...then it's not really going to help anything.

Ideally, you'd drop your rifle onto someone elses's lower trigger/grip assembly and isolate the issue in one go.

[Thenooblord]

Originally Posted by m102404

If you've identified a broken/mangled part...I'd suggest that you stop using it until you sort that piece out. These things are pretty tough on parts when everything is working right...when something's out of wack, you risk breaking something else.

Take a look at some of the pics I've posted...look at the damaged/crunched nozzle. I'm pretty sure that's it started off from some pretty nasty jams...and got worse with more use. To the point where it was not sealing at all. I ran it to destruction on purpose.

I'm not sure how the rifle can triple feed in full auto (or else it'd do it in semi too). Unless there is something majorly wront with your bolt/nozzle assembly and it's alignment/movement with the mag feed lips.

If you start with a clear chamber, full mag of gas and bbs, bolt forward.
- insert mag
- rack bolt all the way back, release
- remove mag
---how many BB's are in the chamber (you might need a rod to clear the barrel)? Should be one. If it's more than one you have an immediate issue with either the nozzle, the feed lips or the bolt. Repeat this test to see consistent results.

If you start with a clear chamber, full mag of gas and bbs, bolt forward.
- insert mag
- rack bolt all the way back, release
- semi auto fire 1 shot.
--shot should leave the muzzle, there should be one in the chamber (clear barrel to confirm. Repeat to confirm

If you start with a clear chamber, full mag of gas and bbs, bolt forward.
- insert mag
- rack bolt all the way back, release
- fire a short burst (ideally 2 shots...at most 4...whatever the number count how many shots)
-- did a shot come out each time?

But again...I wouldn't bother doing any of that until you get the knocker problem sorted out. If the knocker isn't hitting the main valve fully/repeatably...then it's not really going to help anything.

Ideally, you'd drop your rifle onto someone elses's lower trigger/grip assembly and isolate the issue in one go.

I've examined the nozzle/hopup/feed lips multiple times, and I still can't come up with anything that looks like it would cause any problems, so it has me stumped, even more so because it only happens in full auto rather than semi auto. Also, for each double or triple feed, there is a dry fire for each BB that was fired in the one shot, I can't remember if the blanks were before or after the double feeds, I think they were before... so wait now that I think of it it sounds like a jam, yea so why would the gun jam only on full auto?

[m102404]

What were the results of the tests I outlined?

[Thenooblord]

I can't do the tests, the gun cannot fire full auto. I'll have to wait till my replacement knocker arrives.

[m102404]

The first test does even require that you shoot the gun....


Never mind forget it.

[Thenooblord]

well I've done that stuff, but the problem doesn't arise when I do that, it is only in full auto, I have no problems when manually chambering a round, or firing semi auto, so all the tests that don't involve the full auto I have already done, and yield no anomalous results.

For some reason (cooldown maybe making it sticky?) the knocker wont fall all the way down when I fire full auto, so the valve clips the bottom edge and the knocker slips off the top of the valve, so I can't fire full auto, semi works fine though.

[Thenooblord]

I inspected the nozzle again, and i notice a slight displacement in the area where yours collapsed, it appears as if it will eventually end up like yours.
did yours destroy itself from constantly jamming, or just from regular use after the initial damage was done? if I'm going to replace it,
I may as well get the NPAS kit, where did you find yours?

*edit* nevermind, upon closer inspection of the pictures you took, it seems that it is just not precisely cut and it is irregularly shaped, what I had assumed was deformation caused by stress seems to be just poor cutting from the factory

[Bonjour43ma]

Originally Posted by m102404

Bonjour...what rifle do you have? SCAR or M4?

FIRST OFF: No rifle that stops working properly ever magically fixes itself. If something stops working normally...STOP using it. Fix the issue and then continue.

Second: There are a couple of known things with these GBBRs. Such as:
- you much cock the action before moving the selector (cock action, put on safe, load mag, cock action to chamber round...that's a nice safe way to do things)...if you don't and force it you'll break something

- if you have a jam...you can't just keep shooting to try and clear it.
--the steel nozzle will chop/smash bbs and then they'll for sure not go down the barrel...and you'll just be slamming your bolt into the nozzle that won't be able to go all the way forward...not a good thing.
--you CAN try to clear a single/double jam with a mag with JUST gas. It may blow out the jam.
--you're best off to clear the jam with an...SHOCK...unjamming rod (aka cleaning rod). The stock plastic ones are not still enough...get a real .22cal/.243 (6mm) cal rod.
--check the nozzle if you find bb fragments...I've had a piece of a chopped bb lodged inside the throat of the nozzle.

-If you have an M4 and it starts to act up...check to see that the white UHMW spacer hasn't ridden forward and is catching the hammer. It should be all the way back. I put a grub screw in mine to wedge it in place and it hasn't been an issue at all.

Parts to stock up on:
1. Hopup rubber - chopped bbs will tear the nubs off the stock hopup rubber. Nice to have that $3 piece on hand if you need it.
2. Part#66 - the CNC Tool Steel version is very nice. The stock ones are knows to wear out with use. (Warstore guys use/make them...they're shooting/gaming with the M4's a lot and have been wearing them out).
3. Nozzles - although the stock stainless steel one can take an enormous amount of abuse...having a backup one is nice (mine came with two).
4. If you have the "old" M4...switch over to the "CO2 upgrade kit"...which is essentially just the SCAR nozzle/chamber. It looks like that's the nozzle they're going to standardize on. It works, I've swapped mine over.
5. If you have a SCAR...the hinge plate.
6. Fill valves for the mags (MadBull replacement fill valves fit...at least they did for mine...and they're rated to CO2).

As you can see...the above list is pretty thin. More often than not these rifles are workhorses.

Tys

AWESOME info dude! Thanks so much!

I have a WE SCAR btw.

[Thenooblord]

I was tinkering with my trigger group and valve knocker, and I got it to be able to fire full auto again, though not too reliable, but enough for me to notice that the jamming and multi feeding seems to have stopped itself, which is odd because things don't usually fix themselves, and the only difference now being I'm using white .25 bastards instead of black .25 bastards... :S

[Eeyore]

Originally Posted by Thenooblord

I was tinkering with my trigger group and valve knocker, and I got it to be able to fire full auto again, though not too reliable, nut enough for me to notice that the jamming and multi feeding seems to have stopped itself, which is odd because things don't usually fix themselves, and the only difference now being I'm using white .25 bastards instead of black .25 bastards... :S

Sure blame the black guy....

[808]

So... I got Brodie's SCAR.

To make a long story short - the trigger is busted. Off, that is. Busted off. Just like this guy (and a few dozen others it would seem):
http://gasguns.info/forum/viewtopic.php?f=7&t=2045


So, I scoured the interwebs for a few hours to try and find a replacement. No dice. Not even EVIKE carries the WETTI SCAR AWSS trigger. They have the M4 one (and claims that it works on the SCAR), but the dimensions are clearly different.

Then, I emailed WETTI to see about a replacement (where I can get one, and how much $$$). No reply yet - but I'm patiently waiting.

So I started thinking - and now I'm going to make a run of 50 CNC-machined replacements.


If any of you know where I can get a replacement in the mean time, it would be great to be able to use this gun. I haven't even fired a round yet. LOL

[Bamse]

Hi all!

My name is Anders and I live in Sweden. I've been reading this thread for a while and now I've gotten to the point where I really do need to ask some things ^_^

After the release of the specific M4 NPAS package there weren't to many days one had to place an order before the shops over here went out of stock.
Do anyone of you where I can locate a store anywhere in the world that has the M4 NPAS package in stock?

Since the only difference between the SCAR and M4 package is the #39 rod I was thinking of buying the more readily available SCAR kit instead.
After reading m102404's review post in this thread; did the tests on the M4 with the nozzle on the standard guide rod work out well? Did the difference on the threading matter?

All in all, would you guys recommend just putting the NPAS nozzle on the standard rod?

many thanks in advance.

[Hata]

Originally Posted by Bamse

Hi all!

Do anyone of you where I can locate a store anywhere in the world that has the M4 NPAS package in stock?

OOS anywhere and I've asked RA-TECH, they will have more in about 2-3 weeks.

[m102404]

Welcome to ASC.

From what I understood, RATech's whole supply of NPAS kits got snatched up almost immediately. One of the guys on here ordered some about two weeks ago and just got an update that they're still 2-3 weeks out in production. So...you're not alone!

The SCAR NPAS will work with M4...if you have the matching chamber. The "SCAR" nozzle is a different shape from the "old" stainless steel M4 nozzle. I posted some pics where you can see the ridge on the "new" nozzles.

So you need the chamber that will allow it to seat all the way forward. If you get the M4 CO2 Upgrade Nozzle (eventhough I think the slim "old" stainless steel nozzles are designed for CO2)...I think that it comes with the brass chamber.

The chamber is a straight swap in for the existing one.

The NPAS I have in my M4 right now came from a SCAR NPAS kit. Everything is the same between the M4 and the SCAR except for rod length and threading portion.

I don't think that not having as much threading on the rod will negatively affect things...you'll just have to move the adjustment plate out further to reduce the FPS.

The threading on the rod is M4 I think...so you could thread the rod a bit more if you really needed to.

So...in short...yes, I believe that you can use the SCAR NPAS nozzle in your M4. No, I don't believe that you'll encounter any issues with the stock M4 rod not being threaded as much.

I do not believe that the extended length of the rod is super critical...but I do think that the collapsed length of the nozzle/piston/spacer is. Too long and you'll crush your nozzle...too short and it won't seal nicely. If you swap chambers...the clearance might change a bit.

I swapped the hard plastic spacer on mine to a bit of medium-hard rubber. The length is just a hair longer than the plastic spacer. I'm hoping that it'll take up any shock from jams (and if I've not got the length of the assembly right ) and help preserve the integrity of the nozzle. Works fine, I've shot more than a dozen mags through that setup so far.

Best of luck,

Tys

[Bamse]

oh,
now that is the mother of an answer and it covered all my Q's.

Just for clarification;
I do have the WE M4 AWSS Co2 version so the NPAS-nozzle will fit, but after not even 500 shots my WE co2 nozzle got smashed, not totally unlike your pictures, altho mine snapped straight off where yours just is bent. This without a hickup or even a notice that things werent great :/

So, the hunt is basically for a new nozzle, and the one I had was way to hot for the sites over here so i was thinking of going NPAS while im at it
Ofcourse i could do the whole put-a-7mm-bushing-inside-the-#44 dance or try doing a custom bushing ... but ... well ... i just like the NPAS

So, again. Thanks for some very good answers regarding but world wide outofstock-age and also the tech tips. Ill post some pics and report on progress as soon as i get my spares