I'll second that!!.....For my .308 build, I played it safe & went with a complete Aero Upper on the Aero Lower, it snapped together like Legos & is very accurate as well.
AR10 barrel nut problem
- Thread starter ntsqd
- Start date
Help Support Long Range Hunting Forum
One of two things going on. First, check to ensure that BOTH the upper receiver AND the hand guard are of the same compatibility. I.E. high or low profile. They do not intermix. Not sure about cmmg but aero makes their handguards high profile. Second, make sure the nut is clocked exactly with the nut hole at 12 o'clock. If it's off, you must tighten (or loosen) to clock correctly. Be careful to stay within torque specs. It's also remotely possible that cmmg may have bored the clock hole in the nut bad. Does the gas tube slide through it nicely?
DirectDrive
Well-Known Member
With the gas tube and BCG laying on the bench and the barrel nut rotated into its "forever position".....
Look through the carrier tunnel from the buttstock end of the receiver.
Can you see an unobstructed view of the "clover leaf" hole ?
I have build many lg frames
Never an issue when using areo parts
I dont mix and match brands of ar parts especially lg frame .with sm frame ar15 (mil-spec) you can get away with it.
There is no mil spec on lg frame parts. Dpms is a pattern that is the most widely used but companies alway have proprietary parts and designs they feel are better.
Buying all the best parts you like seems great , but all the parts have to work together as a system . Pick a brand and stick with it .
As far as the problem your having i would
1 buy an areo upper
Or
2 file or dremal the groove deep enough for clearance
Gunsmithing offen requires filing drilling dremeling to make parts fit with the clearance needed to function.
I can tell you that you want a loose gas tube that rattles when BCG is lock in battery for accuracy.
Any tension on the gas tube from the wrong Z bend angle into the upper and gas key of carrier will cause unwanted tension on barrel .
Remember the full float theory. No tension on barrel
Never an issue when using areo parts
I dont mix and match brands of ar parts especially lg frame .with sm frame ar15 (mil-spec) you can get away with it.
There is no mil spec on lg frame parts. Dpms is a pattern that is the most widely used but companies alway have proprietary parts and designs they feel are better.
Buying all the best parts you like seems great , but all the parts have to work together as a system . Pick a brand and stick with it .
As far as the problem your having i would
1 buy an areo upper
Or
2 file or dremal the groove deep enough for clearance
Gunsmithing offen requires filing drilling dremeling to make parts fit with the clearance needed to function.
I can tell you that you want a loose gas tube that rattles when BCG is lock in battery for accuracy.
Any tension on the gas tube from the wrong Z bend angle into the upper and gas key of carrier will cause unwanted tension on barrel .
Remember the full float theory. No tension on barrel
ntsqd
Well-Known Member
Making it work isn't a problem for me. Lots of options in the shop/garage. I just wasn't going start modifying without first understanding why the problem exists in the first place. Knowing why might make a difference in the chosen resolution.
I went with the CMMG upper because I wanted the stiffest upper that I could find, and it looked like it might be that. Playing it safe in using only one mfg. leaves options on the table that I might want. I'm willing to deal with, and expect that issues will arise in mixing and matching mfg's parts to get the result that I'm after. Even large frames are legos compared to the conflicts that "Bolt-on" racing vehicle parts have with each other. That part is not a concern.
Folks are getting hung up on the High vs. Low thing and that isn't a factor in this problem. I know this for two reasons, A) the hole in the gas key on the BCG aligns perfectly with the clover-leaf hole in the upper; and B) the Aero hand-guard's rail is exactly flat to the CMMG upper's rail. How two different mfg's held the tolerance stack tight enough for that to happen is a testament to modern manufacturing.
Aero wants pictures, so I guess I have to clean the work bench after all.....
I went with the CMMG upper because I wanted the stiffest upper that I could find, and it looked like it might be that. Playing it safe in using only one mfg. leaves options on the table that I might want. I'm willing to deal with, and expect that issues will arise in mixing and matching mfg's parts to get the result that I'm after. Even large frames are legos compared to the conflicts that "Bolt-on" racing vehicle parts have with each other. That part is not a concern.
Folks are getting hung up on the High vs. Low thing and that isn't a factor in this problem. I know this for two reasons, A) the hole in the gas key on the BCG aligns perfectly with the clover-leaf hole in the upper; and B) the Aero hand-guard's rail is exactly flat to the CMMG upper's rail. How two different mfg's held the tolerance stack tight enough for that to happen is a testament to modern manufacturing.
Aero wants pictures, so I guess I have to clean the work bench after all.....
must be the barrel nut. I'm sure Aero will end up sending out a new barrel nut and then all will be good.
Last edited:
ntsqd
Well-Known Member
No, that is the problem. The groove in the nut isn't deep enough. The lower "tang" in the hole is completely obscured by the nut.
What I don't seem to be getting across to folks is that I know what the problem is and I have several different means to correct it available to me. What I wanted to know is if this is common or unusual. So far what I'm reading is that, even though it shouldn't matter, few have ventured beyond the 'all from one mfg.' formula enough to know, but it is likely an unusual situation.
Does the handguard fit the nut?
If so, the upper is out of spec. Chances that you would receive an out of spec nut and an out of spec handguard are miniscule.
If the handguard doesn't fit the nut, you have an out of spec nut.
Those are the only two options I see.
If so, the upper is out of spec. Chances that you would receive an out of spec nut and an out of spec handguard are miniscule.
If the handguard doesn't fit the nut, you have an out of spec nut.
Those are the only two options I see.
clearly, you got the one-in-a-million barrel nut with a manufacturing defect. Groove is too shallow, blocks the gas tube from going into the cloverleaf, obstructs the hole. You should've bought a lottery ticket that day.
sh!t luck.
Jeffpatton00
Well-Known Member
Tagging in, I've always been impressed with Aero's quality so I'm curious to hear what they say.
Some of Aeros barrel nuts are proprietary to their upper. See below.
DirectDrive
Well-Known Member
Sounds like the barrel nut came with the Aero handguard and is needed to mate up with the Aero handguard.
If you have good, straight-through alignment with your carrier's gas key, then Aero messed up with their barrel nut design or it's exclusive to an Aero upper.
I see a different barrel nut or a modified barrel nut in your future.
If you can't see clear through the nut in this layout, you have a mis machined nut or you are using a low/high handguard and upper receiver. Mismatched nuts don't happen very much. Kinda rare actually. But I've seen several cases of mismatched low/high uppers and handguards. Settle on one profile and replace the odd part.
Being a massive user of AP products I stand behind their fixing it right. Whether it is a high or low tang the gas tube hole WILL be in the same location/height above the threads. The tang only changes height of pic rail. I have had a few barrel nut issues (nuts without the need for aligning of gas tube) that are smooth. With those requiring proper alignment for the gas tube is a PITA (including AP's BAR nut). Do you have the "enhanced" handguard from AP that either uses their (AP) "enhanced" upper or the use of a BAR nut (product # APRH308910) or a non-enhanced version?
Last edited:
