Malfunction: What does this sound like to you?

[SWThomas]

I've got an AR-10 gas gun that's giving me fits no matter what kind of ammo I use. I've tried 3 different Magpul mags and one steel mag and nothing makes a difference. It fires fine when I force feed it one round at a time with an empty mag inserted, but it doesn't always lock the bolt to the rear.

- .308
- 18" barrel
- Noveske Switch Block (rifle length gas system)
- Standard buffer

I've tried Remington Premier 168g, Nosler AccuBond 168g, Nosler Ballistic Tip 168g, Black Hills 168g & 175g, Nosler Custom Competition 168g & 175g, and Copper Creek 175g Gas Gun.

Here's a run-down of the symptoms... I'll insert a fully loaded magazine (20 rounds) and rack the bolt to chamber a round. I'll fire the weapon and get a jam. I observe the jam and the cartridge of smashed by the bolt lugs when going into the chamber. There are lug gouges deep enough into the case where it's unuseable. Sometimes the chambered round will fire and everything will feel right, but when I squeeze the trigger again nothing happens because the bolt didn't strip another round from the magazine. More often than not, I get the jam that I described above. And sometimes (very rarely) the weapon will operate the way it's supposed to for a few rounds before jamming again. Again, it does this with all my magazines and no matter what ammo I use. I'm thinking the intermittant functioning might be due to slight powder charge differences in the factory ammo.

The bolt is always properly lubed with either motor oil or CLP and I always ensure the switch block is on the correct setting.

I'm thinking it's undergassed because the gas port may be too small. What do you guys think???

 

[hlee]

It sounds like you do not have enough gas to operate the gas system. is the gas block seated properly? Is it fully open? I'm sure those more knowledgeable than me will be along shortly to expand on this...

 

[BobD]

It could be a number of things. If you've ruled out any mag issues by testing in another rifle and it never binds manually ....

Where is your brass going after its ejected and any strange signs on casing?

Any new equipment on the mag release? Eg B.A.D. Lever etc...


You might be losing pressure or speed during the cycle causing it to short stroke.

It sounds like its either under gassed or losing gas somewhere.

-leaking at gas key - inspect
-misaligned gas port - check for fouling or powder surrounding
-friction or burr on bolt or carrier - inspect
-bolt to heavy
-buffer to heavy

That's where I would start looking

Hope that helps-

Sent from my iPad using Tapatalk HD

 

[SD26]

Does the buffer go back far enough that it will allow the bolt to lock open on the bolt? Or is it just locking on the bolt carrier? What stock and buffer tube is on the rifle?

 

[SWThomas]

It could be a number of things. If you've ruled out any mag issues by testing in another rifle and it never binds manually ....

Where is your brass going after its ejected and any strange signs on casing? It's going exactly where it should and looks perfect. I collect them up for reloading and they're all in the same spot.

Any new equipment on the mag release? Eg B.A.D. Lever etc... Nope


You might be losing pressure or speed during the cycle causing it to short stroke.

It sounds like its either under gassed or losing gas somewhere.

-leaking at gas key - inspect
-misaligned gas port - check for fouling or powder surrounding
-friction or burr on bolt or carrier - inspect
-bolt to heavy
-buffer to heavy

That's where I would start looking

Hope that helps-

Sent from my iPad using Tapatalk HD

I answered the questions above. Thanks for the ideas.

 

[SWThomas]

Does the buffer go back far enough that it will allow the bolt to lock open on the bolt? Or is it just locking on the bolt carrier? What stock and buffer tube is on the rifle?

It's locking open on the bolt face. It has a PRS stock and I'm not sure about the tube. I would consider that as a possible culprit if not for the sporratic occurence of the rifle operating correctly.

 

[BCP]

Assuming you have the right buffer (the 308 rifle buffer is a different size then a 556 rifle buffer and I think armalite and dpms have diff 308 versions as well) I would think gas issue, possibly misaligned gas block or too small of port size.

If it is a rifle gas 18" then they can be especially finicky and need a larger than normal port to run right.

 

[A10XRIFLE]

I've got an AR-10 gas gun that's giving me fits no matter what kind of ammo I use. I've tried 3 different Magpul mags and one steel mag and nothing makes a difference. It fires fine when I force feed it one round at a time with an empty mag inserted, but it doesn't always lock the bolt to the rear.

- .308
- 18" barrel
- Noveske Switch Block (rifle length gas system)
- Standard buffer

I've tried Remington Premier 168g, Nosler AccuBond 168g, Nosler Ballistic Tip 168g, Black Hills 168g & 175g, Nosler Custom Competition 168g & 175g, and Copper Creek 175g Gas Gun.

Here's a run-down of the symptoms... I'll insert a fully loaded magazine (20 rounds) and rack the bolt to chamber a round. I'll fire the weapon and get a jam. I observe the jam and the cartridge of smashed by the bolt lugs when going into the chamber. There are lug gouges deep enough into the case where it's unuseable. Sometimes the chambered round will fire and everything will feel right, but when I squeeze the trigger again nothing happens because the bolt didn't strip another round from the magazine. More often than not, I get the jam that I described above. And sometimes (very rarely) the weapon will operate the way it's supposed to for a few rounds before jamming again. Again, it does this with all my magazines and no matter what ammo I use. I'm thinking the intermittant functioning might be due to slight powder charge differences in the factory ammo.

The bolt is always properly lubed with either motor oil or CLP and I always ensure the switch block is on the correct setting.

I'm thinking it's undergassed because the gas port may be too small. What do you guys think???

Im assuming its a GAP-10 as you say it has a Noveske Switch Block and your flying our banner.

Try two things

First, Clean the chamber and dry it completely. make sure its in the proper setting on the gas block.

At the range shoot the rifle standing, pull the rifle hard and deep into the shoulder and fire a 3 round mag. Do this a couple times. guys shooting prone often free recoil the rifle which will cause all the problems your having.

Your rifle being 18" and rifle length gas syatem, is a little more prone to under gas issues so its possible the ammo your shooting is borderline on the light side.

Have you shot it with your suppressor??? is it any different suppressed.

Did I talk to you today on the phone??

George

 

[SWThomas]

Im assuming its a GAP-10 as you say it has a Noveske Switch Block and your flying our banner.

Try two things

First, Clean the chamber and dry it completely. make sure its in the proper setting on the gas block.

At the range shoot the rifle standing, pull the rifle hard and deep into the shoulder and fire a 3 round mag. Do this a couple times. guys shooting prone often free recoil the rifle which will cause all the problems your having.

Your rifle being 18" and rifle length gas syatem, is a little more prone to under gas issues so its possible the ammo your shooting is borderline on the light side.

Have you shot it with your suppressor??? is it any different suppressed.

Did I talk to you today on the phone??

George

Yeah, that was me. I keep the chamber clean and dry all the time. I haven't fired the rifle offhand but I can if you want me to. I can do it just to check function, but shouldn't the rifle be reliable when fired in any position? I don't feel like I should have to hold it just right to make it work.

I don't yet own a suppressor so I can't give you any feedback on that. I have tried firing it in both suppressed and unsuppressed modes on the gas block and it has the same issue in both.

 

[springer01]

What he is trying to get you to do is shoulder the rifle correctly so the rifle is recoiling properly to see if it eliminates the problem. The problem being the way you are possibly shooting prone and letting the rifle free recoil.

 

[BCP]

I bet the gas port is just a hair undersized and as soon as it is opened up a bit it'll run and run.

 

[SWThomas]

What he is trying to get you to do is shoulder the rifle correctly so the rifle is recoiling properly to see if it eliminates the problem. The problem being the way you are possibly shooting prone and letting the rifle free recoil.

I got that from George's post. This is my first AR-10 style rifle but I'm not new to shooting. I know how to hold a rifle when I'm prone. Are all AR-10s really that finicky?

 

[springer01]

I got that from George's post. This is my first AR-10 style rifle but I'm not new to shooting. I know how to hold a rifle when I'm prone. Are all AR-10s really that finicky?

Was just making sure what he was trying to get you to do was clear, because reading the following sentence didn't quite seem like you understood.

shouldn't the rifle be reliable when fired in any position ? I don't feel like I should have to hold it just right to make it work.

And yes AR's are tricky to shoot for some people.

 

[cal50]

As others have chimed in you sound under gassed. Make a run to Taco Bell or inspect your gas block, port diameter and related parts.

One thing that I always do is polish the bottom surface of the bolt carrier. It drags less and will not scratch the brass riding against it. It looks nice and cleans up easy as well.

 

[SWThomas]

Was just making sure what he was trying to get you to do was clear, because reading the following sentence didn't quite seem like you understood.

And yes AR's are tricky to shoot for some people.

AR-10s or ARs in general? Because the AR-15 I built myself functions flawlessly in any position. Even if I hold it with one hand, straight out away from my shoulder.

 

[BCP]

I can understand if the rifle were finicky with squib loads ike 40grains 4895 and a 168 but with factory ammo it should run run run even if you are a bit light in the shoulder.

Send it back and let them look it over. It is peace of mind.

 

[Strykervet]

I'd send it back. If it does that repeatedly with several different mags and ammo combinations, then there's a problem somewhere with the rifle. Once they get their hands on it, they'll likely be able to get to the bottom of it fairly quickly, and a good manufacturer won't send back to you junk. If they built it, take advantage of the warranty. Good luck!

 

[Lowlight]

AR10s are not AR15s, they are a completely different animal.

The size and weight of the carrier, the bullet, the trigger... all play a part. Much more mass recoiling much more violently.

You cannot think you can shoot an AR15 and then roll into an AR10 and get the same results unless you understand the characteristic differences. An AR15 is called a Mouse Gun for a reason. Any errors in your shooting will be magnified by 3 with an AR10, and the rifle will absolutely exploit your weakness in position, trigger, etc.

Sure it can be an issue with the gas port, it happens, but it can also be the ammo, the shooter, or any combination of the above.

 

[SWThomas]

AR10s are not AR15s, they are a completely different animal.

The size and weight of the carrier, the bullet, the trigger... all play a part. Much more mass recoiling much more violently.

You cannot think you can shoot an AR15 and then roll into an AR10 and get the same results unless you understand the characteristic differences. An AR15 is called a Mouse Gun for a reason. Any errors in your shooting will be magnified by 3 with an AR10, and the rifle will absolutely exploit your weakness in position, trigger, etc.

Sure it can be an issue with the gas port, it happens, but it can also be the ammo, the shooter, or any combination of the above.

Thanks for the explanation!