AGM M4 GBB

[mutikasha]

They got element nozzles at px airsoft. Is this good news or what?

Ordered a couple immediately, hope there are better then the AGM ones.

[Roecar]

Anyone have the adjusting know on their NPAS break on them? Mine just did and the only way I can now adjust it is disassembling the whole unit and turning it manually... Also I've tried everything possible from adjusting mag heights, shaving some material from the bb loader, etc... but my gun with the full NPAS upgrade is constantly break nozzles and prone to jamming. I've switched the red O-ring out and it still does it. Also on a side note the ROF is almost half on a bad day while maybe 3/4 on a good day.

 

Help?

[Luis21]

Anyone have the adjusting know on their NPAS break on them? Mine just did and the only way I can now adjust it is disassembling the whole unit and turning it manually... Also I've tried everything possible from adjusting mag heights, shaving some material from the bb loader, etc... but my gun with the full NPAS upgrade is constantly break nozzles and prone to jamming. I've switched the red O-ring out and it still does it. Also on a side note the ROF is almost half on a bad day while maybe 3/4 on a good day.

 

Help?

 

What knob are you talking about?

 

Are you talking about the vavle that you open and close with the included key?

 

Man, I'm about to buy a whole NPAS BCG and this is making me rethink my strategy.....

 

-Luis

[snorkelman]

@ruchik

 

you can use any WA GBB M4 compatible barrel you fancy provided you match the barrel nut to the type of shoulder the barrel has

 

thick shouldered barrel (WA or AGM 061/062) use the AGM barrel nut or a WA barrel nut (threading ont he AGM nut is pretty poor so it would be my last choice)

 

narrow shouldred barrel (G&P, AGM 063/064, chinese clone barrels etc) use a real steel barrel nut, G&P barrel nut etc

 

just bear in mind you'll need a buffer tube and castle nut too as the AGM thread is different and isnt going to fit the Kings arms receiver

 

@roecar

 

not mangled one of the adjustable flute valves or chewed a nozzle yet on mine but a few folks have, folks have mentioned adjustable flutes that are bent off centre so can get twisted pretty easily when adjustment tool is used on them.

 

Saw one guy who had teir nozzle foul up from not being screwed home onto the nozzle tube as shipped from RAT, but as you've been replacing a few of them I expect they're screwed fully down In which case look at whatever they're likely to be smakking against (hop unit inner barrel etc)

 

If the gun is feeding BBs cleanly then they shouldnt be getting fouled up on the BBs (might be an idea to manually cycle the gun then pull the bolt carrier group back and use a cleaning rod to push the BB back into the breech, retreive it from inside the gun and look for any marks on it that might suggest a less than smooth feed into the chamber)

 

anyways if you havent been getting misfeeds then I reclon more likely one of these:

 

hop unit being used? compared its length with the AGM one?

 

inner barrel seated properly on the hop rubber and inside the hop unit

 

rubber buffer that sits in upper receiver in front of the charging handle is in place and in good condition

 

nozzle and bolt assembly retracts cleanly quickly and fully into the bolt carrier under spring tension? (I know youve swapped out the red RAT one but still leaves question of wether the one you've replaced it with significantly better)

 

bolt carrier seats nicely when manually racked with a mag in the gun?

 

bolt carrier seats nicely when bolt catch is released on an empty mag?

Edited August 30, 2009 by snorkelman

[ruchik]

Wrong place buddy, not a good idea to try and get around the 100 post rule for the sale forums by posting that.

 

In other news, if I want to use the KA MBK and decided to use the stock barrel, I don't even need the barrel nut the kit comes with?

[Luis21]

Wrong place buddy, not a good idea to try and get around the 100 post rule for the sale forums by posting that.

 

In other news, if I want to use the KA MBK and decided to use the stock barrel, I don't even need the barrel nut the kit comes with?

 

If the barrel nut is for thin shoulder collar barrels then you don't need it nor can you use it properly.

 

Anyways guys, I ordered an RA-Tech NPAS Steel BCG, 8 nozzles, ang 6 5KU mags. I am alsmost done with my build, all I need is a real AR-15 recoil buffer and it'll be good to go. I'll post my observations.

 

-Luis

[snorkelman]

depends wether it has WA compatible barrel nut that suits your AGM 061/062 barrel, or comes with a G&P compatible barrel nut instead

 

if it comes with WA style one? use that in pref to the AGM nut

 

if it comes with a G&P nut you're going to have to use the AGM nut (or go out and buy a WA nut, a different barrel or alter the AGM barrel shoulder to suit)

 

 

[mutikasha]

Just a quick question before some modifications.

Does lower fps setup (with green gas) gained with modding the nozzle means more power on the blowback?

Is this also the case with NPAS?

Sorry if it is a dumb question.

[snorkelman]

posted for slu over at gasguns info, but I may as well post it here case theres anyone finding their hammer lock fitting is of the 'turn the air blue' variety as it can sometimes be a pita

 

 

if you find the hammerlock difficult heres one option you might want to try

 

 

fit the spring into the hammer lock and clip a cable tie around it all, that'll remove the chance of the spring and hammer lock parting company either as you try to fit them in the receiver and get the logn leg past the selector, or once you've done that and you let go of them to fit the axis pin thru. You can (hopefully) see the long leg of the spring pointing backwards away from the long leg of the hammer lock at this stage. when you fit the parts the long leg of the spring should be pulled forwards so its pointing in front of the long leg of the hammer lock, as thats what puts the spring coils under proper tension. The AGM and a few others tend to fit the spring in the incorrect position with the leg pointing towards the rear of the receiver and having correct level of tension in the coils of the spring is really hit and miss if its fitted that way (Ino got it right by fitting it pointing forwards)

 

 

this is where the springs long leg sits when the selector is between safe and semi - in the groove thats cut in left hand side of the selector. Note that particular selector is a 3round burst one so it wont look exactly same as a normal one but the groove is in the same place, also note that I've taken this photo in a primered and stripped receiver so its easier to see the spring leg - you'll also need the trigger fitted when doing it for real. Thats the other reason for fitting it pointing forwards - when the spring leg is in that groove then standard one sided selectors cant pull out of the receiver when set to safe as they could do otherwise and the selector itself benefits from the tension that the spring leg is applying to it (less prone to being loose and rattly)

 

 

Anyways, back to fitting - as you cant get the gun into safe without the hammer wanting to be cocked it might be easier of you leave the hammer out (or remove it) untill the hammer lock is in place, that way you should be able to set the selector to safe without a cocked hammer having to get in the way of your fingers.

 

I find it slightly easier to fit the lock and spring when the selector is set to safe as the spring leg only has to be pulled forwards enough to clear the groove, though I usually do it with the cocked hammer in the way.

 

You can fit it regardless of where the selector is set to so if you want the hammer left in and uncocked while doing it then fit it while selector is in semi or auto.

 

 

a cable tie drawn around the parts will pull the coils of the spring much closer to the inside of the hammer lock than they're meant to be when the axis pin goes thru, so they wont line up fully with the holes in the sides of the hammer lock Instead of trying to get the axis pin thru at that stage use an allen key thats much narrower than the real axis pin as a temporary fixing, it can be wibbled n wobbled to make its way thru the coils of the spring

 

Once the allen key is thru all the holes and cois of the spring just snip the cable tie off

 

Then just fit the axis pin in from the opposite side (dont forget first washer when it makes its way thru the receiver) withdrawing the allen key as you do so. When the axis pin has got passed the first side of the hammer lock and needs the coils lined up you can wobble the allen key around to get the coils lined up where you need them, likewise when its exiting the opposite side of the hammer lock as you finally pull the allen key almost all the way out slip the second shim between that side of the hammer lock and the inside wall of the lower reciever. Then push the axis pin fully home into that other side of the receiver and the allen key is removed completely

Edited September 1, 2009 by snorkelman

[Roecar]

not mangled one of the adjustable flute valves or chewed a nozzle yet on mine but a few folks have, folks have mentioned adjustable flutes that are bent off centre so can get twisted pretty easily when adjustment tool is used on them.

 

I talked with RATech to get a cheaper replacement for about $5, how ever shipping is insane so I'm waiting till I need another mass order from RATech

 

Saw one guy who had teir nozzle foul up from not being screwed home onto the nozzle tube as shipped from RAT, but as you've been replacing a few of them I expect they're screwed fully down In which case look at whatever they're likely to be smakking against (hop unit inner barrel etc)

 

Mine are definitely tightened down. I suspected that maybe the G&P rubber was too tight causing bbs to get stuck that would in turn destroy the nozzle. I also suspect that my nozzle maybe unscrewing itself with the hard recoil.

 

If the gun is feeding BBs cleanly then they shouldnt be getting fouled up on the BBs (might be an idea to manually cycle the gun then pull the bolt carrier group back and use a cleaning rod to push the BB back into the breech, retreive it from inside the gun and look for any marks on it that might suggest a less than smooth feed into the chamber)

 

I do notice some oil/grease on the BBs but no indentations.

 

anyways if you havent been getting misfeeds then I reclon more likely one of these:

 

hop unit being used? compared its length with the AGM one?

 

inner barrel seated properly on the hop rubber and inside the hop unit

 

rubber buffer that sits in upper receiver in front of the charging handle is in place and in good condition

 

nozzle and bolt assembly retracts cleanly quickly and fully into the bolt carrier under spring tension? (I know youve swapped out the red RAT one but still leaves question of wether the one you've replaced it with significantly better)

 

bolt carrier seats nicely when manually racked with a mag in the gun?

 

bolt carrier seats nicely when bolt catch is released on an empty mag?

 

I'm using the Prime WA type hopup with a G&P hopup that I'll be replacing with an RATech. The Prime has insanely tight tolerances so I am certain that the inner barrel and hopup assembly are meshing together correctly, I think its the rubber thats causing problems.

 

I definitely need a new buffer for the upper receiver as mine has completely disintegrated. For the moment I have some vinyl tape and caulk doing the job until I can get new ones.

 

As for the proper bolt seating that I am not sure, when I manually charge the gun I do notice the mag does push the bolt up a hair or two. I'm not sure if thats supposed to happen to ensure a tighter seal or if that is causing my problems. And FYI I am using GHK mags.

 

Btw, thanks for the input. You help send me in a better direction than I was going.

[snorkelman]

aye you do seem to have most of them covered already

 

minor deflection on the bolt assembly as it rides over the seal on the mag shouldnt be a problem all my GHKs do the same and original white plastic nozzle RAT fit in the nozzle tube as standard is still in minty condition on mine regardless of that.

 

The lack of proper buffer in the upper might be having an impact (pardon the pun) might be allowing the nozzle to enter the hop unit further than its meant to go in the loading part of the stroke (a sticky nozzle tube might let the bcg return to battery with nozzle still slightly extended toom, which would do much the same)

 

On mine the nozzle does end up fully sealed hard against the breech during blowback part of the stroke, but during loading BB and firing stage the charging handle standoff keeps it ever so slightly out from in full (based on the thickness of that rubber buffer and thickness of the front of the handle itself)

 

if the tape and caulk you've substituted isnt holding it out as far (or the inside fof the front of your charging handle has taken a beating from the steel gas key and gotten really worn down) then it could be entering just a little further than it should at that part of the cycle, and thats the part of the cycle where it'll be getting the biggest smack if it is entering slightly too far

 

tried a bit of thread lock to see if there is an unwinding issue? there should be some loctite grades that will hold it steady without near permanently bonding the parts together

 

 

How much damage is it showing before a failure? little nicks right at the lip or a bit more heavily scored/further along the length of the nozzle?

 

If you do break another one post a photo of it removed from the tube Other than that only thing I can think of is buying some of the cheaper plastic ones and surrendering a few to the gods (trim quarter mil off one if it breaks trim half mil off the next etc till you either hit a length thats short enough to stop it or the nozzle ends up so shortits performance goes thru the floor)

 

[snakedoctoror]

Hi Guys,

 

 

I have had a AGM M4 for a couple of months now although been an airsofter a while now i am in no way an expert on these things. What i would really lik to know is . I'm wanting to change my barrel to the same length as the WA as i want to put my novasake on. it looks gash on the standard M4 so can anyone tell me where can get barrel parts. then what i need to do to modify it. other one is my hop ain't the best. can i do anything to get it to work better. starts dipping around the 25m mark. Has anyone heard if the mags will be getting any lighter. i carry 6 just now and by god there heavy.

 

 

cheers in advance

[teflon don]

the agm mag are actually the worst in every way

if you want light ones go for the hgk ones

 

you can improve your hop by adding tape around the hop up bucking (or buying a new bucking (or a entire new unit (the stock one will break anyway)))

 

you can buy cheap barrels on gunnerairsoft.com i would recomend the ra tech ones (they are tight bores)

 

[mutikasha]

Been doing some thinking...don't know if this had been discussed before in WA themes...

Could the damage to part #2 be from compressional stress rather than extensional (extensional has a bit more logic in it but hey...everything isn't always logical).

My #t part broke off in the standard place but along with it came of a little part of #1 where these two meet. Examining the charging handle it doesn't look as it suffered any kind of stress which leads me to the conclusion that maybe the front part of the nozzle is the part that stops the bolt from moving in the firing position and thus a lot stress on the back part of the nozzle. Maybe installing some kind of buffer between part #2 and the bolt carrier (at the end where it slams it) and maybe sanding a bit from the whole front part of the nozzle. Spare AGM nozzles should arive tomorrow, tinkering weekend ahead.

Any thoughts?

 

Btw. still waiting on the answer for that fps/blowback ratio question.

Anyone lowered the fps on the AGM without using a RAT NPAS, just with tinkering with the stock nozzle.

 

M.

[Stealthbomber]

Bit of a random one...

 

I keep reading people talking about only loading a mag with the gun cocked.

I've never needed to do that.

 

Take the striker block apart and make sure the striker is completely free to move backwards and forwards.

The bottom edge of the striker should be curved.

I suspect this will wear with use. Most people seem to report bent gas release valves soon after buying the gun.

You can still modify the striker by making the radius bigger and smoother to allow mags to go in easier.

Just make sure you don't actually reduce the overall length of the striker. Just curve the bottom-front corner.

[snakedoctoror]

the agm mag are actually the worst in every way

if you want light ones go for the hgk ones

 

 

 

does the HGK ones work in the agm's i didnt think or know if they did. the mags weight a tonne. especially running around all day with them.

 

thats for the help with barrels

[Badly Browned]

does the HGK ones work in the agm's i didnt think or know if they did. the mags weight a tonne. especially running around all day with them.

 

thats for the help with barrels

 

Do you mean GHK? Yes they work in my AGM M4, and are significantly lighter.

[snorkelman]

Bit of a random one...

 

I keep reading people talking about only loading a mag with the gun cocked.

I've never needed to do that.

 

on both of mine you really do need to - striker already moves perfectly freely right back to its fully disengaged point within the firing block - nothing obstructing its travel when that part is out of the gun or when the hammer is cocked

 

whats limiting its travel is the amount of standoff available between a fired hammer and the rear of the striker. Even if the part was radiused more on mine to allow an easier time for the mag valve, theres still a point in the insertion of a mag with hammer dropped where either the mag valve is going to start getting deprressed, or the striker is going to have to move further back towards the hammer than its free travel allows.

 

As the hammer and its spring are putting up stronger resistance than valve and its spring, its the valve that yeilds first (you can hear the gas)

 

If I slammed it in hard I dare say it would latch in place but if the valve trips far enough to engage the valve lock then the mag is going to vent or the rifle is going to cycle

Edited September 2, 2009 by snorkelman

[Stealthbomber]

on both of mine you really do need to - striker already moves perfectly freely right back to its fully disengaged point within the firing block - nothing obstructing its travel when that part is out of the gun or when the hammer is cocked

I think there's actually a different cause for this...

 

Like every GBB, the hammer pushes the striker forward with each shot and then should move back again slightly afterward.

 

Take a look at the lower receiver with the hammer de-cocked and you can see that there's a gap between the hammer and the hammer spring.

That gap is there to allow the hammer to fall back slightly which, in turn, allows the striker to sit in a better position.

 

Try moving the hammer backwards and forwards slightly, without cocking it.

You should find that, if you push it forward, it'll stick in the forward position.

Now (without cocking the gun first) pull the trigger and try moving the hammer again.

The hammer now moves freely. It won't stick in the forward position. It relaxes backwards.

 

There's a couple of different issues at work here.

Firstly that the radius on the front edge of the striker isn't ideal, which makes it harder to insert the mag.

Secondly, that the bottom faces of the AGM hammer are roughly cast which causes it to stick.

Thirdly, that people might be releasing the trigger too quickly after taking a shot.

 

If the striker and hammer are functioning smoothly (and you keep the trigger pulled until the gun is back in battery, just like Costa Coffee tells you to) then you should never have any problems with loading mags.

 

I must say, I'm wondering if it might also be worth fitting a stronger spring to the striker?

Obviously there's a risk that'll mess with the function of the gun but I suspect it'd have to be a helluva spring before it got in the way of the hammer striking significantly.

 

*EDIT*

Something glaringly obvious which I forgot to mention... cos it didn't occur to me.

 

If you've been dry-firing the gun without a mag in the chances of this being an issue are HUGELY amplified.

If you've fired the gun without a mag in (and you don't trust your hammer to be free enough to relax) then it definitely IS worth cocking the gun before loading another mag.

[snorkelman]

nopes in case of mine neither currently has an AGM hammer both are using RAT hammers and the five bearing one of those is supplied machined and polished smooth as a bald mans head

 

Likewise on hammer bounce - I'm sitting with a lower to watch it all and have drect access to the hammer, and even physically setting the hammer forwards from its usual rest position so its practically sitting straight up with front face almost vertical (to simuate a hammer that hasnt bounced back as it normally would) makes no difference. The amount of force that needs applied to the striker to get the hammer to then return to where it normally sits after a bounce is negligable - valve meeting the striker would/does cope with that.

 

however once its moved the hammer back to the usual bounced poition that just returns things to where they normally are - any further upwards pressure on the mag sees the mag valve yeild and depress to accomodate the striker that being path of less resistance for it than it start depressing the hammer and its spring.

 

edit to clarify - when my hammers bounce back from hitting the striker they bounce as far back is is mechanically possible for them to travel - ie they rest in a position where the rear of the hammer is already sitting against the central strut of the hammer spring. Theres nowhere further for those hammers to fall back to without load getting put on the hammer spring.

 

On mine I'd be tempted to have a futz around and shorten the overal length of the striker itself. Primarily cos when it strikes a GHK valve its travel can be enough to see the valve ocassionaly stick open but I'll probably leave it as is till some spares of it show up for sale on their own.

 

the hassle it brings to most mag changes I find pretty minimal - generally the bolt catch will be holding the bolt carrier and hammer etc back at time a mag change is needed, and if the hammers dropped on a mag thats chambered a round but run out of gas, then the hammer is going to need recocked anyway, and in that situation better to do that before you stick another mag of BBs in than after, otherwise you'll have a double feed.

 

The only real annoyance from it is when you have the hammer sat in fired position and no BB up the spout (bolt catch hasnt tripped on last round) - as then you need to rack the BCG once to cock the hammer and then either fire a dry shot, or rack it a second time to chamber a BB

 

double edit -

It might come down to how consistent the AGM springs are produced - I know that on the burst fire hammer spring theres a little more releif behind the hammer as the legs that run up to the central spar of the spring are longer and at a completely different angle (neither is actually enough to allow the striker to clear completely but enough to let the burst hammer rest a little more angled back)

 

If AGM are having all their hammer springs made at one place then Id assume the legs are always the same lengths across all the full auto hammer springs they do, but there might be inconsistencies in the angles, allowing some hammers to rest further back than others

Edited September 2, 2009 by snorkelman

[snorkelman]

had a spy thru my bits and yep two different hammer springs

 

One is wider at the bottom (if you look from the back the two sets of coils sit at an angle tapering closer as they reach the top) and the angles are different

 

both hammers bounce back fully but the bar of spring that runs behind the hammer on that one sits slightly further back - allowing the hammer to sit at rest slightly further back and allowing the firing block to retract just over a mm more than the other one does

 

neither of mine allow it to sit far enough back to let any of the mag valve pass, but if theres more variations than the two Ive got that may well explain differences between one gun and another and why some can.

 

 

 

different widths of the lower leg spacing

 

 

 

side on shot showing differences in the angles of the AGM springs (RAT burst kit hammer spring on left for comparison - note the RAT hammer has much longer and slghtly wider U shaped top section than the U shaped top section of the two AGM springs)

Edited September 2, 2009 by snorkelman

[HOPPERSAN]

Anyone up to comprising a list of confirmed working and drop in compatible parts or can you link one ? thanks. The rear of the nozzle cracked after 400 rounds and I am looking at b.c.g upgrade or just replacing the stock nozzle with the 12 dollar replacement . My rifle is stock otherwise. I am not looking for any thing pretty just want the gun to fire and last a full skirmish dont care to much about fps just durability

Edited September 3, 2009 by HOPPERSAN

[Luis21]

Anyone up to comprising a list of confirmed working and drop in compatible parts or can you link one ? thanks. The rear of the nozzle cracked after 400 rounds and I am looking at b.c.g upgrade or just replacing the stock nozzle with the 12 dollar replacement . My rifle is stock otherwise. I am not looking for any thing pretty just want the gun to fire and last a full skirmish dont care to much about fps just durability

 

 

Hey,

 

Why don't you give this one a try?

 

http://www.px-airsoft.com/showroom/model/T...515472968003644

 

Someone from here ordered like 5 but he hasn't reported back yet...

 

My RA-Tech NPAS BCG should come in tommorrow and I'll test it out on Saturday.

 

It's $260 though. I spent that much hoping that I would never have to replace anything but nozzles ever again.

 

-Luis

[HOPPERSAN]

thanks luis that is what I was looking at please let us know how yours works out .

[Luis21]

thanks luis that is what I was looking at please let us know how yours works out .

 

No problem man. And yes, I might even write a review on it if I have time.

 

-Luis