Aero Precison AR10 issue

[Alibiiv]

My son recently put an Aero Precision AR10 together in .308 Winchester. He replaced the adjustable gas brake with an Aero adjustable one. We took the rifle to the range to shoot up some 150gr ammo. Right out of the gate while trying to adjust the gas block the rifle refused to cycle. We sent so far as to nearly turn the screw totally out of the gas block, like 15 clicks of adjustment, and then the rifle would cycle some of the time. He called the factory who told him to polish out the inside of the bolt where the lock up is due to the chance there "might" be some over spray that the put on the bolt to prevent the bolt from rusting????? He did say that he polished out where they told him to polish and that he is bringing a regular AR buffer spring to see if that helps if the polish job didn't work. I am no guru at all with ARs and asking out if anyone else has experienced this with the Aero Precision AR10s? And if so what was the remedy for this issue?? As always opinions really are appreciated and thank you for the help as I am not much of an AR person and trying to find some help with this ARs issues.

 

[sea2summit]

Help me out with "refused to cycle".
Bolt didn't move?
Didn't eject?
Stove pipe?
Didn't feed the next round?
Didn't strip the next round?

Next set of questions:
Are the holes on the adjustable block aligned and did he make sure he has flow?
Was he shooting suppressed? Has he shot it suppressed before?
How many rounds through the rifle?
Factory ammo?
Are all the ring splits offset on the bolt (may or may not make a difference but never hurts to check)?
Post a pictures of the brass, any swipes etc. or gas moving along the case unlike bolt action where you just see over pressure at the primer there are a lot of the other parts of the brass that give indicators if something ain't right.

 

[rpol98]

did it work before you replaced the original adjustable gas block with the Aero adj GB?

suppressed or unsuppressed?

is it a normal BCG? or one of those suppressor-optimized BCG's? the suppressor-optimized BCG will barely run unsuppressed on full-gas.

 

[cohunt]

My guess is when he put the new gb on-- he didn't align the holes in the block with the hole in the barrel correctly --- not all gas blocks should be set fully against the shoulder.

Is it a clamp on gb or set screw style?

 

[Alibiiv]

Help me out with "refused to cycle".
Bolt didn't move?
Didn't eject?
Stove pipe?
Didn't feed the next round?
Didn't strip the next round?

Next set of questions:
Are the holes on the adjustable block aligned and did he make sure he has flow?
Was he shooting suppressed? Has he shot it suppressed before?
How many rounds through the rifle?
Factory ammo?
Are all the ring splits offset on the bolt (may or may not make a difference but never hurts to check)?
Post a pictures of the brass, any swipes etc. or gas moving along the case unlike bolt action where you just see over pressure at the primer there are a lot of the other parts of the brass that give indicators if something ain't right.

At first the rifle refused to cycle, then as he backed out the screw on the gas block it started to eject, but the bolt would not stay open on the last round. After some firing the bolt would feed the next round, but that only happened like every two or three times then he would have to eject the round and pick up another. He did get a few rounds that did not eject when we first started to adjust the gas block, but we expected that at first until it was adjusted to where the rifle would cycle, but that never did happen.

 

[Alibiiv]

did it work before you replaced the original adjustable gas block with the Aero adj GB?

suppressed or unsuppressed?

is it a normal BCG? or one of those suppressor-optimized BCG's? the suppressor-optimized BCG will barely run unsuppressed on full-gas.

The rifle is suppressed and he did not try it with the fixed gas block, he went right to the adjustable one.

 

[LaHunter]

You state that this is an Aero Precision AR10, but you replaced the original gas block with an Aero gas block?? Wouldn't the original gas block be an Aero gas block? Is this a 'mostly Aero' AR10? I am no AR10 expert, but you can read posts on multiple forums about AR10s being prone to problems when they are put together by individuals with parts from different manufacturers.

 

[Alibiiv]

You state that this is an Aero Precision AR10, but you replaced the original gas block with an Aero gas block?? Wouldn't the original gas block be an Aero gas block? Is this a 'mostly Aero' AR10? I am no AR10 expert, but you can read posts on multiple forums about AR10s being prone to problems when they are put together by individuals with parts from different manufacturers.

Yes the original was an original however not an adjustable on it was fixed

 

[bamban]

On the range, load a round, drop mag. Press down on the bolt stop. Keep the bolt stop pressed while you fire a round. If the gas system is sufficient, the bolt will stop on the way back.

If mechanically pressing the bolt stop did not stop the bolt, fix the gas system.

If it stop, look for mechanical interference.

 

[sea2summit]

At first the rifle refused to cycle, then as he backed out the screw on the gas block it started to eject, but the bolt would not stay open on the last round. After some firing the bolt would feed the next round, but that only happened like every two or three times then he would have to eject the round and pick up another. He did get a few rounds that did not eject when we first started to adjust the gas block, but we expected that at first until it was adjusted to where the rifle would cycle, but that never did happen.

Sounds like the adjustable block is not actually on the barrel's gas port like it should be.

 

[sea2summit]

On the range, load a round, drop mag. Press down on the bolt stop. Keep the bolt stop pressed while you fire a round. If the gas system is sufficient, the bolt will stop on the way back.

If mechanically pressing the bolt stop did not stop the bolt, fix the gas system.

If it stop, look for mechanical interference.

This is not totally correct. Just because it will lock back does not mean it's properly gassed. In the 10 platform it actually travel significantly past the bolt lock for proper ejection and to reliably feed the next round as the mags position the rounds a little slower than than the 15's. And aside from that why not just use an empty mag?

 

[bamban]

This is not totally correct. Just because it will lock back does not mean it's properly gassed. In the 10 platform it actually travel significantly past the bolt lock for proper ejection and to reliably feed the next round as the mags position the rounds a little slower than than the 15's. And aside from that why not just use an empty mag?

No comment.. you must be an expert.

 

[Roughrice]

You should have PLENTY gas pressure to cycle with the suppressor on!
Normally the adjustable block is to cut down to tame the violent pressure created with suppressor.
If not fired with original gas block… you could have an obstructed gas port or insufficient gas port size on the barrel or as mentioned before, misalignment of gas block to port.
If it cycles smoothly and locks into battery by hand then it it's definitely a gas issue.

Try another brand of ammo while you're at it just to eliminate an ammo issue.

I've built many of them and fixed many with gas issues. Even AR's from mass produced manufacturing have low end defective components .
I've had to bore gas ports on barrels, drill out obstructed gas blocks and tubes as well as properly align gas blocks.
You should also soak the bolt with oil and work the bolt back and forth in the carrier when new to "wear-in" .
Run it wet!

 

[Roughrice]

Also, there is an ejection clock position where your ejected brass must fly out at 4:00 in a properly gassed weapon.
Any forward or rearward ejection from that angle indicates under or over gassed operation.