AGM M4 GBB

[andy_mace]

do agm do 30 round mags aswell as 50? cheers

[beretta]

what should I check if my agm m4 is not feeding? From what I can see the loading nozzle does not move back with the bolt carrier after pulling the trigger. I have to manual cycle the bolt with the charging handle to get a new round in.

 

 

Check the above and then also check there's no friction between the nozzle and the receiver bushing that the hopup sits in. i think it was the AABB nozzle i was using and it was getting stuck in that.

[stirrat]

do agm do 30 round mags aswell as 50? cheers

 

 

No

[raito]

you could always modify the mag so it only holds 30 bb's. easy enough to do...

[stirrat]

YOU could or something really easy,.. wait for it..... yes thats right only put 30 bb's into the magazine, i know it's ground breaking stuff comming outta my kitchen!

[hessu75]

Hello again ya all,

 

Trying to source a new short outer barrel for AGM M4.

 

What would be the correct length for it to reach the front sight only?

Cant measure the barrel at this moment. Out of town.

 

Is there a "stubby killer", or a "tanker"- front end for the AGM M4?

 

Cheers

 

-Hessu-

[Batmause]

http://rsov.com/index.php?target=products&product_id=5506

I have ordered one.

[mindwreck]

hessu you need the 9" length barrel. that will end directly after the gas tube/front sight assembly

[Luis21]

Heads up guys.

 

I just got word from another member that a real AR-15 barrel nut screws onto the upper receiver threads without a problem.

 

I have a Socomgear Daniel Defense Mk.18 RIS II that is RS threaded and I will let you know how it works on my AGM.

 

Thanks,

 

-Luis

[hessu75]

hessu you need the 9" length barrel. that will end directly after the gas tube/front sight assembly

 

Yeah,

 

Got the 9" outer barrel and it is installed now.

Was a little bit of hazzle with the shims and with the barrel nut. Handguard would not lock into place at first, but that was just little adjusting.

 

Now, I need the folding front sight and then I am a happy camper. AEG ones will fit?

 

Cheers

 

-Hessu-

[raito]

I tried my A&K S-System front folding sight on my AGM, it fits no problem...

[HOPPERSAN]

HI question ..my agm has been an on the shelf project just pull it down when i have some free time . I have installed the aabb nozzle w npas and have everything in properly i think but the rifle will not cycle properly .. I have taken the outer barrel assy off so I could narrow down the issue. My agm will fire fine if held upside down the bolt cycles fine but if held properly all I get is a small puff of gas then i cycle the charging handle and again small puff of gas . turn the gun upside down and I can get a regular shot off ..I have no play in the magazine at all so I am lost any help would be great thanks ..

Edited June 17, 2010 by HOPPERSAN

[Luis21]

HI question ..my agm has been an on the shelf project just pull it down when i have some free time . I have installed the aabb nozzle w npas and have everything in properly i think but the rifle will not cycle properly .. I have taken the outer barrel assy off so I could narrow down the issue. My agm will fire fine if held upside down the bolt cycles fine but if held properly all I get is a small puff of gas then i cycle the charging handle and again small puff of gas . turn the gun upside down and I can get a regular shot off ..I have no play in the magazine at all so I am lost any help would be great thanks ..

 

Open your NPAS valve more towards the blowback cycle and also make sure that the O-ring at the rear of the nozzle isn't too tight. Beware of the red AABB o-rings, they swell with lube to the point that they will get the nozzle stuck inside the carrier.

 

-Luis

[HOPPERSAN]

Thanks luis .. I only have a black o-ring - and had to sand it down a little so it would not sick in the bolt I do not think I went to far I am home now and left the gun at work so I will give it a try latter . Thanks again for your help 1 more dumb question if it is to tight can i just stretch it.

[Luis21]

Thanks luis .. I only have a black o-ring - and had to sand it down a little so it would not sick in the bolt I do not think I went to far I am home now and left the gun at work so I will give it a try latter . Thanks again for your help 1 more dumb question if it is to tight can i just stretch it.

 

Too tight as in it doesn't moove inside the carrier or that it doesn't fit around the rear of the nozzle?

 

-Luis

[HOPPERSAN]

Hi Lewis... so I got back to my gun today and took the bolt down there are a couple thing I have noticed .

First is that the nozzle shell I had just installed broke at the back top of the nozzle where my original had broken bummer because I just got it and only had a couple bad dry fire shots out of it .

I also noticed that the 1 of the 2 small o rings on the npas was broken , the one that has its own milled grove for it to sit in , not the one on the adjustable threads.

 

So I pull out the second spare nozzle shell I ordered and try for round two . The next problem I ran into was that the holes for the retaining pins for the nozzle were not drilled correctly from the factory with a little work I got it everything together minus the broken small o-ring because it was so thin I could not see it doing much but I may be completely wrong .

 

Dropped the bolt in the gun and I have the same problem . just a little puff of gas / then hold gun upside down and it fires .

 

I backed off the npas and had the same issue . My bolt moves freely and I have checked the hop up barrel nut to make sure it is not binding when in full battery .

 

I have stopped at this point because this is my last nozzle shell . If you have any other suggestions I am looking . Thank you for your help so far .

Also I am not looking to put a bunch of money and thought i would be able to make a fun plinker with clone parts rather than RA-TECH stuff so if there are any new clone stuff you think might give me a better chance of getting this up and running please let me know .

Edited June 22, 2010 by HOPPERSAN

[raito]

@Hoppersan: Why dont you just get the JDT complete BCG, its been working great for me, I've put thru more than 3000 rounds thru and have had no problem, I've even jumped into a lake with my rifle and it still shoots great

[HOPPERSAN]

@Hoppersan: Why dont you just get the JDT complete BCG, its been working great for me, I've put thru more than 3000 rounds thru and have had no problem, I've even jumped into a lake with my rifle and it still shoots great

I was told it would be to heavy and did not want to risk it. Its nice to know its been working good for you though. I will really look into that . thanks

[raito]

It is a bit heavy, the rof goes down in full auto, but I rarely use auto anyway, there is also less recoil, but the trade off is that you get a very sturdy nozzle...

[mutikasha]

I haven't met a plastic nozzle that endured the torture of more than 1000 shots. In fact some of them gave out on me within 100 rnds. I now moved to ACM alu nozzle and the thing is very well made. Nozzle tip slices trough jammed bb-s like they are nothing - plastic tips break on such occasions. The problem you get when using alu nozzle is that your side lock plate gives out within 50 rnds if it is plastic. There is a steel or alu one that can be obtained trough RA-Tech. Also, the nozzle tips are interchangeable wit RA-Tech ones.

For your problem that gun only fires when up side down - try pushing the mag a little bit more in when trying to fire from the normal position even if you think there is no play - there always is. If this doesn't help, try tinkering with your magazine maybe although I don't know what could be the problem if it was magazine related.

[PoleCat]

Hey guys, im gona ask for your help on a mather, and in return il show you a picture of my setup.

 

Problem:

The nozzle gets stuck in the front while the BC cycles backwards thus breaking the plastic bit that holdes the nozzle from going out of the BC.

 

I have 2 possible explanations to why it does this. First, if i cycle manually, theres quite a bit of resistance to get the BCG into place, its really tight fit over the magazine, if id guess its like 2-3 mm to tight.

Second, its because ive changed the upper to a Vltor upper from AABB/G&P dont remember the brand. I didnt have this problem before. and i used the upper on the std agm lower so its not the new lower its the same dimensions, ive checked.

 

Ive also tryed 4 diffrent nozzles (had the laying around), and the AABB full metal one, is the one thats get stuck (im guessing its the weight), the others doesnt get stuck but they do slide bad, and thus ive broken the plastic bit thats holds it into the bc with those aswell.

 

So i want to use this upper, but what do i do to fix this, i need to take away material somwhere, but where ?

 

[Edit] could it be that the hopup-houseing is slightly of its position so the nozzle will have to turn a bit, and thus making the kontakt to the magazine in an angle, and thus get further down and creating friction ?

 

 

as promised a picture:

[mutikasha]

If it cycles normal when manually cocking it while the magazine isn't in, then your obvious solution is to shawe of some materila from the mag catch so it sits a bit lower.

Using alu nozzle you will very quickly brake your side lock plate no mater what if it's plastic.

[PoleCat]

Yea it cycles lovely without the magazine in. Might give shaving the mag catch a thought.

 

But ive also thought about it, if i cycle it manually both fast and slow i cant seem to get the result that the nozzle stays and the boltcarrier goes back, but i guess i cant replicate what happens when gas is used and what forces are in play.

 

The full alu nozzle came with a plastic lock plate, i think thats kinda stupid, any idea where to find a metal one ? also it doesnt seem to work very well, im gona go back to the plastic nozzle until ive sorted out this issue.

[mutikasha]

RA Tech sells Alu and steel side lock plates. 10 and 15 $ a piece.

You cannot replicate the action of the BCG by manually cocking it. That is because the charging handle is designed to pull back the nozzle along with the bolt carrier. Try taking it out of the body...you will get it.

Is cocking it difficult when the magazine is in?

[PoleCat]

I kind of solved 2 problems.

 

It wasnt that the nozzle got stuck, it just looked that way, the problem was that the nozzle got pretty far out of the BC that it shifted upwards, and the sharp edge from the nozzle's back (im using a NPAS, and its the edge of plastic nozzle not the NPAS), got caught on the bottom edge of the BC making it unable to go back into the BC once cycled.

 

This was solved by sandpaper that edge down and bending out the bottom in the whole of the BC (apperently when firing with another Bolt catch unit, it was sitting a little high, and thus bending that part of the alu BC).

 

 

The other problem i did as you said, i sandpapered down the mag catch until the magazine no longer made it difficult for the nozzle to make contact with the hopupunit.

 

This made that problem go away, but once i noticed this, i also noticed when test shooting that sometimes it doesnt load another BB (this happened sometimes before aswell), and this is caused (i think) by 2 problems:

 

If the magazine is pressed upwards the tight fit problem, still exists ( need to come up with a soloution to build up som material on the underside of the mag catch so that it sits there firmly.

 

The other more delicate problem i think is solved by a stronger spring wich pulls the nozzle back into the BC (I noticed that that spring is very weak compared to other nozzles i have with npas or not). Because what i think is happening, is that the spring is too loose and too long, that the BC makes its full cycle, but the nozzle is to slow, so it never moves back fully to pick up a new BB, well sometimes it does.

 

PS. I would kill for a highspeed camera DS