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

[Shirley]

Anyone know a good method how to stop leaky mags? I've just used the blue gasket method.. The gasket seals for the WE mag is so thin ans flimsy..

[El Cactus Loco]

word on the street is lithium grease is the way to go for tricky mags. doesnt lose performance in cold temps like the ones created by cool-down.

[Hata]

I also heard of lithium grease to fix mag leaks. But where can I find this kind of lithium grease? I believe those from crappy tire or HD not safe for rubber on airsoft, right?

[m102404]

I just got two mags that were sealed with silicone gasket sealer. HOLY CRAP that stuff stinks!!! Close to I'm going to barf stink.

This stuff does peel off nicely though...so I cleaned it out and tried white silicone grease. Can Tire, automotive section, usually close to the loctite/gasket sealer/grease/etc...you can get a big tub of it, but a tube goes a long, long way.

I greased up the "o-ring" seal and put it back together. I then used overly oiled gas to fill the mag. Worked perfectly the first time. There was some "grease blowout" with the first couple of mags of gas...so I just vented the first mag, I'll have to remember to swab out my barrel later.

[Shirley]

I used the blue gasket maker. Put it over the gasket, then tighten half way, wait an hour and then tighten full and wait a bit over 24h and no leaks!

[m102404]

How do you stand that smell?!?!

A note on sealing stuff up.....

On the mags that I looked at there was significant rust on the screws that hold the back plate onto the gas resevoir. I suspect the mag was washed clean to remove any oil/grease before it was sealed with the gasket stuff.

Doing so though resulted in LOTS of corrosion to the screw heads and thread bodies of the screws. Enough so that the holding power of the threads were compromised.

You might want to pull one screw at a time and check them...

One of the holes in the main part was stripped out...you can use a slightly larger self tapping screw to replace the stock one. It seems to be holding well.

But, I'd advise against washing off the screws....unless you take steps to protect them from corrosion again, or replace them with new ones (they're standard screws).

Tys

[El Cactus Loco]

yah use brake cleaner to clean those parts....

[rustysniper]

OK.....I have a problem that I can't seem to piece together with my M4.
I did 2 things...
1) Installed RA Tech NPAS
2) Attempted to do a semi only conversion on the selector

Now....when I press the trigger all it does is blow off all of the gas. I tried a bunch of different mags with the same effect.

Help.....

[m102404]

With the upper off...

If you cock the hammer, does it:
- trip the knocker back
- stay cocked

When you trip the hammer, does it:
- knock the knocker out

Then when you cock it back, does it do what it did in the first step? If yes...your lower is fine (at least so far).

With the upper on, it's knocking the mag and the gas is venting into the nozzle.

- is the bolt going back at all? If not, your float valve might not be closing...does it move freely
- no issue with manually racking the bolt? guessing not
- try adjusting it so that the float valve is as far back as possible
- check all your o-rings
- take a good close up pic of your nozzle, valve, spacer, rod and post it

[Thenooblord]

or maybe just at the same time you did the work, the firing pin delay stop broke

[rustysniper]

With the upper off...

If you cock the hammer, does it:
- trip the knocker back YES
- stay cocked YES

When you trip the hammer, does it:
- knock the knocker out YES

Then when you cock it back, does it do what it did in the first step? If yes...your lower is fine (at least so far).

With the upper on, it's knocking the mag and the gas is venting into the nozzle.

- is the bolt going back at all? If not, your float valve might not be closing...does it move freely NO
- no issue with manually racking the bolt? guessing not NO
- try adjusting it so that the float valve is as far back as possible (in reference to the front of the nozzle?)
- check all your o-rings (looks good)
- take a good close up pic of your nozzle, valve, spacer, rod and post it will do

Question....could I have screwed up the positioning of the selector in the receiver that would affect it?
__________________

[m102404]

If your float valve, the little valve inside the nozzle, does not move forward (towards the muzzle) it will not close the gas system and start the recoil phase...no bolt moving backwards, no trip of the knocker, knocker stays forward and keeps pumping out gas until the mag is empty.

So pull your bolt.
- take a close look at the nozzle
- use a little screwdriver/pick/rod/fingernail and see if you can push the float valve forward...it should move freely, but there is a little spring tension..
- it should pop back when you let it go.
- if it's not doing that, take a close look at the o-ring on it, pull the nozzle apart and test fit it without the spring (don't shoot it like that, just test fit by hand).

The float valve MUST move freely and seal tightly when it's forward. I mic'd the specs of the valve...but it's in the workshop somewhere.

Tys

[m102404]

OH! also...does your old nozzle and new nozzle look exactly the same. I.e. outside shape, size, etc...

Or does one have a big ridge on the outside and the other is more of a slim bottle shape?

The original nozzles were slim bottle shapes...the new ones have a big ridge around the outside (looks like the SCAR nozzle).

If you are going to ask for pics of the two....go back to the beginning of this thread and search for pics.

[m102404]

pic of the semi/full paddle and spring

[rustysniper]

OK...got it so it looks like the pic above.
Now.....if I put a mag in and try to charge the gun.....it won't....the charging handle stays back. If I take the mag out and charge it there is no problem and the bolt returns. When I put the mag back and pull the trigger it still dispells all of the gas.....

This is a bummer