AGM M4 GBB

[Badly Browned]

I'd say the trigger guard near the grip looks busted. Is it even attached?

 

So the tiny O-ring in my AGM magazine valve keeps coming loose. Very frustrating.

 

And I noticed that my WA magazines are a bit more difficult to insert when filled with propane.

Edited June 27, 2009 by Badly Browned

[stew_b_10]

ill say he snapped the lower receiver tab when replacing the trigger guard.

 

my 062 shipped yesterday.

[Roecar]

ill say he snapped the lower receiver tab when replacing the trigger guard.

And we have a winner

I'd say the trigger guard near the grip looks busted. Is it even attached?

Its attached via the MIAD, the enhanced trigger guard comes with the full kit MIAD

I was going to say it looks like the bolt is cracked the long way at the very top...

Nope, its working just fine.

Either you have bad barrel distortion (no pun intended) on your camera lens, or your stock tube doesn't look aligned to the receiver. Am I wrong?

Its my crappy camera work

Edited June 27, 2009 by Roecar

[stew_b_10]

you can either give me the cookiez or just get my 062 shipped faster. i can't track it on speedpost yet.

[ruchik]

So I got mine today.

 

The good:

-solid, no creaks.

-awesome fun.

 

The bad:

-bolt locks back only when manually racked, not when firing on empty mag. Even then, only catches some of the time when manually racked. I believe this is the mag's fault-I think the fix where you file away a bit of the lock lever on the mag it should clear itself up, or maybe a stronger spring for the lever.

-loose barrel. 3-second fix by turning the delta ring.

-loose stock. Easily fixed with a little tape.

-the mag weighs more than the gun! It's seriously the same weight as an actual brick.

-mag does seem to swell up after filling with green. Pretty tight squeeze.

-mag cannot be inserted without first racking the bolt. I tried reaching into the magwell and manually pushing the hammer back, but it's impossible. It doesn't budge unless the bolt is racked.

[Luis21]

Ruchik:

 

When field stripping the gun do you have alot of trouble pushing the takedown pins back in? Do you need a punch and hammer to push out the pin when field stripping?

 

-Luis

[ruchik]

Haven't tried field stripping it yet.

 

Upon closer inspection, the catch itself seems to be rough. It doesn't move smoothly up and down, it clicks up and down, almost like it's catching on something. I'll open it up and take a closer look later. I'm too busy annoying my roommates with it right now.

[Luis21]

Haven't tried field stripping it yet.

 

Can you please try field dtripping it? It doesn't take more than a minute and no parts will fall out since it was designed to be taken apart quickly.

 

Or anyone else? Do you guys have problems with the takedown pin?

 

Thanks,

 

-Luis

 

[Stealthbomber]

So I got mine today....

To address some of your concerns...

 

There is no spring that works with the lever in the mag. It's the magazine spring that pushes the lever upward.

The only way to increase the spring tension is by either replacing or pre-tensioning the magazine spring.

Maybe, as with midcaps, the thing to do is fit something behind the spring to compress it slightly?

 

Not too sure what you couldd file on the mag to improve this.

The metal lever on the mag is the one that operates the magna valve system. It's nothing to do with the bolt catch.

The 2-part lever that actuates the bolt catch already has the full range of possible movement. Nothing will improve the range of movement.

It might be feasible to drill a tiny hole in the lever that operates the bolt catch and screw a grub-screw into it so that it can push the bolt catch slightly higher but it's a fiddly job I wouldn't fancy doing to a full load of mags.

 

 

I've noticed the same thing when inserting the mag. It makes me cringe to see idiots slapping mags in forcefully. They're gonna break something eventually.

When you strip the gun you'll notice that the hammer has about 5mm of free play.

When fired (with no mag in) the hammer moves forward and stays there due to friction, leaving the striker fully forward.

This is why you can't insert a mag.

If you shoot the gun with a mag in the spring (and gas) pressure shuts the valve which pushes the striker backwards.

When you remove a mag under these circumstances another mag should go straight in with no problems.

A mag empty of gas might not push the striker back sufficiently but, under normal circumstances, you'll be swapping mags when it's empty of BBs and, at that point, there should still be enough gas to close the valve and move the striker backwards.

Or, in short, under normal skirmishing conditions this shouldn't be a problem.

 

Finally, I see more and more people are showing up saying their mag's swell up.

Kinda reminds me of when I was the only person who dared say the G&G L85 was a POS.

[falconfour4]

Take down pins are fine in mine. not too tight and not too loose

[Stealthbomber]

Can you please try field dtripping it? It doesn't take more than a minute and no parts will fall out since it was designed to be taken apart quickly.

 

Or anyone else? Do you guys have problems with the takedown pin?

 

Thanks,

 

-Luis

Dude, it's a pin. How hard can it be?

 

Seriously, I mean, there are some simple checks that anybody with an IQ greater than 60 could think up all by themselves.

 

Has it ALWAYS done this since you've owned it?

If it HASN'T then you need to look at some of the monkeying around you've been doing.

If it HAS then you need to investigate further.

 

Release both pins, remove the upper receiver, set it aside and look at the lower by itself.

Try putting the pins back now.

If they go in then it looks like you're just struggling to get things aligned properly.

If the pins DON'T go back in then you need to look at why.

 

Both pins have a spring-pin that holds them secure(ish) and stops them falling out.

If you undo the stock locking ring and screw it back you'll release the spring-pin for the rear receiver pin.

Remove the rear receiver pin and try to refit it in the LEFT side of the receiver.

If it doesn't go in you know the hole is too small.

Now try inserting the rear pin into the front hole from the LEFT side.

Again, if it won't go in it's because the hole is too small.

 

If the pins WILL fit into the left-side holes fairly easily then the only remaining possibility is that the pins aren't made correctly and this is stopping them from seating properly or, possibly, stopping the spring-pins seating against them correctly.

 

Is there some reason why this is bothering you so much?

Does it feel like the receiver isn't closing properly or like something's being forced?

It's common for receiver pins to be tight at first because of paint. Once you've worked them a few times they usually get slack enough that you'll be more concerned about losing them.

[Luis21]

I was just asking to know if someone had the same problem as me, not to get a guide on how to fix it.

 

It has to do with bad tolerances from the factory. The upper and lower reciever holes weren't aligning correctly so they would let one pin go in smoothly but then it would throw off the other pin and not let it go in without using a hammer forcefully.

 

I fixed it now and the pins are smooth.

 

Now all I have to do is:

-Reinforce the RIS

-Reinforce the gas tube connection with the upper reciever

-Reinforce my snapped bolt catch(I think I'm going to get a steel RA-Tech catch instead.

 

With these kinks I think it's going to be ready to go.

 

-Luis

[ruchik]

Well the pins go in smoothly, but now I have another problem. The mag straight up shoots all the gas out from the top. I was moving the gun around with the mag in, and suddenly, inexplicably, the gun just went off full auto and emptied all the gas. Whenever I try to fill it with gas, all of it just shoots out, whether the valve lock is depressed or not. Took it apart to replace the o-ring listed on Redwolf as a possible leaky ring, but to no avail. Now when I reassembled it the valve lock doesn't move up and down smoothly anymore, it gets stuck. The metal rings under the delta ring are bent and broken from tightening too much, that's my fault. Is the mag leaking from the top because an o-ring on the valve is unseated?

 

Forgot to mention. The G&P seal kit fits the stock AGM mags. The PGC hopup kit also works, but is a tight fit.

Edited June 28, 2009 by ruchik

[Roecar]

Did anyone else notice that King Arms has released multiple styles of "stamped" MBKs for WAs GBBR? So far they have Vltor, Troy, and Stag Arms/Vltor. These could be the next big things for GBBRs and afforbalde to maybe. At the very least it'll be cheaper than Prime MBKs.

[Stealthbomber]

Well the pins go in smoothly, but now I have another problem. The mag straight up shoots all the gas out from the top. I was moving the gun around with the mag in, and suddenly, inexplicably, the gun just went off full auto and emptied all the gas. Whenever I try to fill it with gas, all of it just shoots out, whether the valve lock is depressed or not. Took it apart to replace the o-ring listed on Redwolf as a possible leaky ring, but to no avail. Now when I reassembled it the valve lock doesn't move up and down smoothly anymore, it gets stuck. The metal rings under the delta ring are bent and broken from tightening too much, that's my fault. Is the mag leaking from the top because an o-ring on the valve is unseated?

 

Forgot to mention. The G&P seal kit fits the stock AGM mags. The PGC hopup kit also works, but is a tight fit.

Sounds like the release valve is dodgy somehow.

As I've said, I KNOW the machining on mine is a bit dodgy. If I sping the middle part with my fingers I can feel it going loose and then tight.

When it's tight it'll wedge open and the spring pressure isn't enough to close it.

This might be your problem as well.

 

I'm a bit baffled by the parts you've broken.

You mean you've damaged the weld spring and/or the circlip behind the delta ring?

There shouldn't be any pressure on those parts when you're tightening the barrel nut.

Are you pressing on the delta ring and turning that rather than tightening the barrel nut?

[Luis21]

Who here has ordered directly from RA-Tech?

 

I'm going to order a bolt stop from them but I just want to know how good their customer service and how fast their shipping is. They look like a great company.

 

-Luis

[T0p Sp!N]

... The mag straight up shoots all the gas out from the top. I was moving the gun around with the mag in, and suddenly, inexplicably, the gun just went off full auto and emptied all the gas. Whenever I try to fill it with gas, all of it just shoots out, whether the valve lock is depressed or not. Took it apart to replace the o-ring listed on Redwolf as a possible leaky ring, but to no avail. Now when I reassembled it the valve lock doesn't move up and down smoothly anymore, it gets stuck.

 

I got mine yesterday and have the same leak/problem.

When the mag is inserted, the gun fires full auto (weak/short stroked).

 

I haven't stripped the mag down yet though, so I'll have to try that and check out the O-rings.

[jonny2400]

Ok I said that today I would use my AGM and give a full report as I was playing!

 

However, I can't it broke within the first Mag, A the time, I was unsure what happened, I was firing on Semi- Got about 4 off then nothing!

 

After making a check, The mag has failed. The Valve has completly froze. It will not move even 1mm. I took the mag apart and removed the valve. After some gentle tapping it still would not move any amount, At this stage I knew the valve was for the bin. It took a number of heavy blows with a hammer to move the valve!!!

 

Anyone have any idea why this happened?

[Damien]

Can someone link me to the mods that need to be done to use GHK mags in the AGM M4? I know the mag catch needs to be filed down, but is there anything else? I can only get it to work if I remove the upper receiver, push the mag in, then push the upper back down. Something's blocking it, I can't figure out what. GHK mags are slightly taller than AGM mags.

 

Edit: It was the upper receiver being slightly misaligned that's blocking the GHK mag. Since its really tight. A little filling on the corners of the mag made them fit.

 

AGM mags that are leaking: I took mine apart and made sure every seal had silicon oil on it. It couldn't hold any gas when I first got it, the o-rings were all dry. After I let it oil a bit, it held propane fine.

 

Prime hop up for AEG barrels on AGM M4: The hopup chamber is so tight, it stretches the hopup rubber. I had to cut about a quarter inch off and soak it in silicon oil to make it fit, and it's still tough to get on. Once it's on, it's not moving anywhere.

Edited June 29, 2009 by Damien

[snorkelman]

put mine back together for a test fit and noticed that athough the ino hammer lock is a drop in fit it wasn't actually functioning

 

With receiver open both hammer locks swing into place when selector is switched to auto, as you'ld expect them to, but only the AGM one actually catches the hammer

 

AGM hammer lock - pull trigger in auto and hamer drops for first shot, as hammer is recocked for second shot (while trigger is still held back) the hammer lock grabs the hammer and holds it in cocked position untill the bolt carrier is almost fully forward

 

at which point rear of the carrier disengages the hammerlock and allows the hammer to fire, which in turns forces the valve knocker forward into the magwell where it would strike the mag valve. So by time valve is being struck the bolt carrier is fully forward and bolt is lined up with gas port on the mag

 

Ino hammer lock - pull triggrer in auto and hammer drops for first shot, as hammer is recocked for the second shot (with trigger still held back) the ino hammerlock fails to grab the hammer, and as the bolt carrier begins to travel forward, theres nothing to hold the hammer and prevent it from just following the bolt carrier forwards....

 

As a result the hammer fires and forces the valve knocker into the magwell when the boltcarrier is still around 1cm to 2cm shy of being closed and not yet fully lined up with gas port on the mag

 

Above is with Ra-Tech bearing hammer installed I'll have another go tomorrow with orginal AGM hammer but as it stands Id stick with the AGM hammer lock when using the AGM receiver.

Edited June 29, 2009 by snorkelman

[messenjah]

Who here has ordered directly from RA-Tech?

 

I'm going to order a bolt stop from them but I just want to know how good their customer service and how fast their shipping is. They look like a great company.

 

-Luis

 

I ordered from ratech via mail, great communication, fast shipping, to Czech Republic (in the middle of Europe..) in 5 days

[Luis21]

I ordered from ratech via mail, great communication, fast shipping, to Czech Republic (in the middle of Europe..) in 5 days

 

 

Sounds good. I just recieved an email from them and they sound like they mean business.

 

-Luis

Edited June 29, 2009 by Luis21

[Stealthbomber]

I think I've figured out where my AGM mag is leaking from.

 

The moving part of the valve is assembled on a stainless steel shaft (part #220) and there's a brass plug (part #221) fitted onto the end of the shaft.

There's a small o-ring seal fitted between the shaft and the brass plug to ensure no gas can pass through the centre of the plug.

I can see this o-ring is not seated correctly and I'm pretty sure gas can pass through the tiny gap between the shaft and the plug that fits over it.

 

No idea what I'm actually going to do about it yet.

[Badly Browned]

That small O-ring your talking about is the exact o-ring that keeps getting dislodged on my magazine. It is bone dry atm though, I need to get more silicone oil. But atm I can't even get through one mag before that o-ring comes loose.

[Luis21]

Anyone out there running a 6 AGM mag rig yet? I don't care if it's heavy, I'm going to run one in a few weeks.

 

-Luis