Help diagnosing my AR10

[Goodknight]

The rifle
Complete 100% Aero Precision M5
•18" Aero Precision assembled upper with I assume a non adjustable gas block.
•Nickel Boron BCG ( disassembled cleaned lubed)
•CMC trigger
•AP M5 buffer tube, spring and buffer
• AP M5 charging handle
Magpul 10 round magazine


The issue
Rifle will chamber first round and go close full battery
Rifle will fire and eject first round
Rifle does not chamber another round...

I purchased every part.
bought assembled upper
I assembled lower

My first thought is gas issue...
Buffer?
Buffer spring?


Pretty disappointed that a 100% AP rifle does cycle.
I'll also reach out to Aero P on Monday
Thank you for any and all help!

Read More

 

[arakboss]

The rifle
Complete 100% Aero Precision M5
•18" Aero Precision assembled upper with I assume a non adjustable gas block.
•Nickel Boron BCG ( disassembled cleaned lubed)
•CMC trigger
•AP M5 buffer tube, spring and buffer
• AP M5 charging handle
Magpul 10 round magazine


The issue
Rifle will chamber first round and go close full battery
Rifle will fire and eject first round
Rifle does not chamber another round...

I purchased every part.
bought assembled upper
I assembled lower

My first thought is gas issue...
Buffer?
Buffer spring?


Pretty disappointed that a 100% AP rifle does cycle.
I'll also reach out to Aero P on Monday
Thank you for any and all help!

What ammo were you using?

 

[Goodknight]

308 perfecta
308 Federal
Factory loads

 

[223to45]

does it try to chamber?? Or does it not even catch the next round??


Does it lock back on single round??

 

[deadeye]

Have you tried manually cycling it? Is it the standard carbine buffer or the heavy one? Did you try more than one mag/or brand to rule it out as cause? Wouldn't be the first time that a gas block wasn't placed right also.

 

[Goodknight]

It racks fine, heavy but fine.
Buffer I assume is standard. When ordering I did not see option for HD version.
did not try multiple mags should have...
Do not want to pull upper apart to check gas tube placement till I talk to Aero Precision...

 

[Goodknight]

does it try to chamber?? Or does it not even catch the next round??


Does it lock back on single round??

Closing bolt chambers a round from magazine.
pull trigger round fires and spent case ejects
Then trigger clicks on empty chamber.
did not check lock back. Should have

 

[Goodknight]

does it try to chamber?? Or does it not even catch the next round??


Does it lock back on single round??

It does not grab another round...

 

[Goodknight]

Sorry for hurky-jerky responding new to forum

 

[AlaskinAssasin]

Sounds like your bolt isn't coming back far enough...I see this a lot with guys doing their first couple builds...

First, could be a lack of pressure. Usually from misaligned gas block...

Second... rifle length buffer in a carbine length tube/ wrong spring... either or

Third, out of spec mag (least common)

 

[ssasquatch]

Just a thought - pull your buffer spring out and leave the buffer in the buffer tube.
slide BCG into buffer - does the BCG clear the back edge of the mag?
should have roughly 4mm clearance between the BCG and rear of Mag when BCG is full engaged in buffer tube.
Also what position is your brass landing? Anything past 3 clock and the rifle is over gassing.
What weight ammo are you running?

 

[Goodknight]

Just a thought - pull your buffer spring out and leave the buffer in the buffer tube.
slide BCG into buffer - does the BCG clear the back edge of the mag?
should have roughly 4mm clearance between the BCG and rear of Mag when BCG is full engaged in buffer tube.
Also what position is your brass landing? Anything past 3 clock and the rifle is over gassing.
What weight ammo are you running?

average 160 grain
Pulled spring and yes looks like BCG clears mag...
Did not think of brass throw will have to check that at range.
I made sure gas tube is clear
could buffer spring be to heavy?
I

 

[Goodknight]

Sounds like your bolt isn't coming back far enough...I see this a lot with guys doing their first couple builds...

First, could be a lack of pressure. Usually from misaligned gas block...

Second... rifle length buffer in a carbine length tube/ wrong spring... either or

Third, out of spec mag (least common)

when looking down hand guard gas block looks correct.
Can buffer spring be too strong?
Actually that is my main suspicion

 

[Goodknight]

when looking down hand guard gas block looks correct.
Can buffer spring be too strong?
Actually that is my main suspicion

as I said earlier I went 100% with Aero Precision M5 parts. Stands to reason when a person orders the Aero Precision M5 buffer tube assembly it should work...wrong to assume anything I guess.
although there is a definite difference between rifle and carbine.
which one in your opinion do I need?

 

[Goodknight]

Just got on the AP website and there is both M5 carbine buffer kit and M5 rifle buffer kit.
I looked at my order history and I purchased a carbine length buffer kit... wonder if that is problem

 

[ronin223]

Aero Per built upper so I am gonna assume gas block and gas tube are good but they need to be checked because you never know.

The BCG is that Aero as well. Remember it is a AR-10 build, so is it a DPMS or armalite spec bolt which will cause headspace issues. which does not seem like what is wrong

AR-10 buffer tube is that the correct one or did they get it mixed up with an AR-15 buffer tube. If a ar-15 buffer tube with ar 15 buffer the bolt will not go all the way back to pick up a round.

Is it a carbine AR-10 buffer OR a shorter one for use with AR-15 buffer tube.

Is the spring a carbine length spring or a rifle length spring. Did they give you the wrong one. Rifle should be around 11.75 inches Carbine should be around 10 inches

Try shooting just one round and seeing if the bolt will lock back. but it sounds like either your gas port size is wrong, your gas block is loose or misaligned, gas tube is loose or broken, your buffer is the wrong size, your buffer tube is the wrong size, or your buffer spring is the wrong size.

Also check the gas key if it is loose it will act like you are undergassed

Got a friend with an AR-10. swap out parts till you see if it will run. assuming his is also a DPMS pattern gun

An AR-10 IS NOT A AR-15 you need to play around alot more to get it to work. parts are not as interchangable as a AR-15

 

[Goodknight]

Aero Per built upper so I am gonna assume gas block and gas tube are good but they need to be checked because you never know.

The BCG is that Aero as well. Remember it is a AR-10 build, so is it a DPMS or armalite spec bolt which will cause headspace issues. which does not seem like what is wrong

AR-10 buffer tube is that the correct one or did they get it mixed up with an AR-15 buffer tube. If a ar-15 buffer tube with ar 15 buffer the bolt will not go all the way back to pick up a round.

Is it a carbine AR-10 buffer OR a shorter one for use with AR-15 buffer tube.

Is the spring a carbine length spring or a rifle length spring. Did they give you the wrong one.

Try shooting just one round and seeing if the bolt will lock back. but it sounds like either your gas port size is wrong, your gas block is loose or misaligned, gas tube is loose or broken, your buffer is the wrong size, your buffer tube is the wrong size, or your buffer spring is the wrong size.

Also check the gas key if it is loose it will act like you are undergassed

Got a friend with an AR-10. swap out parts till you see if it will run. assuming his is also a DPMS pattern gun

An AR-10 IS NOT A AR-15 you need to play around alot more to get it to work. parts are not as interchangable as a AR-15

Thank you!
Entire build is Aero Precision
There is no cross contamination of M4 to M5
Gas block is aligned and air passes freely
No gas key as I do not believe it is adjustable style
I'm thinking I purchased a Aero P carbine length buffer tube When what I needed was a rifle length buffer assembly. To much tension fir BCG to cycle back with carbine spring...
thoughts?

 

[Goodknight]

See pics

 

[ssasquatch]

One issue I had with my last Aero build was the gas block I used. It may look lined up, but the barrel gas port might not be lined up directly with gas block.

Light rounds might be an issue, but you can always get a Sprinco lighter buffer spring.

I ran that with my 6.5 creedmoor build, solved problem. But that was with a 130 eld-x round

 

[Goodknight]

One issue I had with my last Aero build was the gas block I used. It may look lined up, but the barrel gas port might not be lined up directly with gas block.

Light rounds might be an issue, but you can always get a Sprinco lighter buffer spring.

I ran that with my 6.5 creedmoor build, solved problem. But that was with a 130 eld-x round

Thank you! I believe I need to swap out the "carbine" buffer tube kit for a rifle version