I built an AR-10 completely out of Aero Precision parts and with three or four different types of ammo, I can manage about a 5.0 MOA. Not.5, but 5.0 at 100 yards.
Someone told me that you can adjust the gas block to increase or decrease the timing of the BCG being blown back to mitigate that.
Any truth to that, or does anyone have any other ideas?
Thanks

I don’t know that it would make that much difference, but what cartridge is the rifle chambered for, and what ammunition produces 5 MOA results?

.308. I have tried True Velocity, Federal, and Winchester.
Odd thing about the TV ammo, about 90% of the polymer cases ruptured.

Well, their are a lot variables that can contribute to shooting performance issues.
Perhaps you could fill in the blanks unless you just want to blame it all on Aero Precision.

I am curious if you have used the True Velocity ammunition in other rifles. Although perhaps the problems I had have been fixed by the manufacturer, but I found it to exhibit indifferent precision as well as failures to fire and overpressure issues.

https://sigforum.com/eve/forum...935/m/9850030594/p/1

If I am correctly imagining how the TV stuff ruptured, I certainly would not shoot any of it in my guns. In addition to being unsafe for the shooter, case ruptures can damage the firearm.

I don’t have a lot of experience with adjustable gas blocks, and because of the problems I had with the only fully-adjustable one I every owned, I’ve avoided them since. I don’t, however, recall ever seeing any claims that their settings would have significant effects on precision. It might make sense that there could be some variations due to barrel harmonics or something else, but 5+ MOA with different ammunition types? I will be curious to see the answers to your question, but I am skeptical at this moment.

I have an AP chambered in .308 but use a Criterion M110 patterned barrel (20" at 1:10 twist) (from Fulton Armory) with a correctly head-spaced bolt. It prefers 168 grain SMK's from Federal. If I do my part 1.5 to 2 MOA is achievable.

If you do have an adjustable gas block then you need adjust it such that it cycles cleanly (i.e. cleanly ejects cases, does not hang up, and as you said slamming the bolt against the buffer). Are you using a carbine or rifle length buffer? Do you have the correct buffer spring to match the buffer? What type of trigger are you using? Just for starters.

5moa?

Until you tell us everything, it's just your fault.

My Scar 17 loves Federal match 168 gr. but shoots anything with acceptable accuracy.
I would go to the Federal ammo, and ask somebody that is a very good accuracy shooter to try and shoot a tighter group.
If that fails I would suspect the chamber, especially if you are getting ruptured cases.

AR10's can be challenging to shoot, but 5 MOA?

As others have said, try FGMM 168 gr. which is generally considered some of the best/most accurate .308 ammo. And if you have a friend that is a solid bench shooter to shoot a few groups.

Only other obvious answer is to check check rings, scope mount, etc. to make sure nothing is loose. I sometimes help my local club with site in days just before hunting season and you'd be surprised how many people show up with loose scopes or other obvious issues with their gun.

Are you shooting irons or and optic. If the later what kind of mount. I would shoot a federal 150 ball and stick to it until you can figure out the cause. You should be able to shoot 2" groups at a 100yds with regularity.

I've had a very negative experience with Aero Precision AR-10 functionality and spent more than $250 trouble shooting the AP Upper before sending it back to Aero Precision. The reason I delayed sending it back is the solid reputation for quality enjoyed by AP.

They ultimately replaced the BCG and the gun runs fine, no problem with shooting 2 MOA. not wishing to let my negative experience influence my comment I went to Chat GPT and asked it to search the gun forums on the Internet and summarize the comments about AP AR-10 accuracy. Here's what it said:

Based on a review of approximately 50 user comments from forums such as Reddit's AR10 and Aero Precision, as well as Sniper's Hide, the sentiment regarding the accuracy of Aero Precision's M5 AR-10 platform is mixed. Here's a breakdown:​

Sentiment Summary

"Positive/Neutral (~60%): Many users report satisfactory accuracy, achieving around 1 MOA (Minute of Angle) with quality ammunition and proper tuning.​

One user noted, "Built a lot of Aero M5 with BA barrels... All 1MOA performers with right ammo and tuning." ​

Another shared, "I was able to group 5 shots to look like a 4 leaf clover they were so close to each other." ​

Negative (~40%): Some users express dissatisfaction, citing inconsistent accuracy and quality control issues.​

A user mentioned, "I have been frustrated with the lack of accuracy from it. I probably average 3+ MOA, with anything but M118LR/FGMM 175gn." ​

Another stated, "The biggest issue by a long shot is the shitty barrels that Aero uses."​"

ChatGPT ends here.

Customer Service at Aero Precision truly sucks. I wouldn't discount a manufacturing problem with Aero Precision. The first thing I can think of is your muzzle crown done properly? You have my sympathy as you go forward trying to fix this issue.

All of the speculation is fruitless without the OP coming back in and telling us more details.
Otherwise this is just a rant.

quote:

I would shoot a federal 150 ball and stick to it until you can figure out the cause. You should be able to shoot 2" groups at a 100yds with regularity.

I'm just curious on this. In anohter thread here accomplished shooters shooting match 5.56 struggle to do 2". I would never expect ball ammo to do that out of a .308 and my semi .308 guns will not. Without more from the OP of course real suggestions are not possible... but expecting ball ammo to do consistant 2" groups IMO is a bit too much.

What is everything you need to know?

100% AP.
18” BBL.
Rifle length buffer.
From a bench.
Everything set with proper torque.
All spent brass (and polymer) zings out with zero issues.
Upper rail with Warne rings and Leupold scope.

I apologize, I thought you needed help with a problem.

quote:

Originally posted by hrcjon:

quote:

I would shoot a federal 150 ball and stick to it until you can figure out the cause. You should be able to shoot 2" groups at a 100yds with regularity.

I'm just curious on this. In anohter thread here accomplished shooters shooting match 5.56 struggle to do 2". I would never expect ball ammo to do that out of a .308 and my semi .308 guns will not. Without more from the OP of course real suggestions are not possible... but expecting ball ammo to do consistant 2" groups IMO is a bit too much.

Factory Federal 150 grain fmj should be good ammo. A 2" group at 100 yds should be considered average accuracy from a decent shooting AR10 with it.
My suggestion is also to use one ammo and shoot it to figure out where it shoots. Shooting three of four differents ammo's is going to complicate things dramatically. Ymmv

post photo's cheap ar10 10 shot 2" group with ball ammo.

quote:

What is everything you need to know?

what ammo are we discussing?

He did say what ammo he has used so far.

It seems, to me, that the logical approach would be to contact Aero about the ruptured TV cases. Surely that indicates a chamber problem, and they'd likely respond by sending a replacement barrel for him to try.

quote:

Originally posted by KSGM:
He did say what ammo he has used so far.

It seems, to me, that the logical approach would be to contact Aero about the ruptured TV cases. Surely that indicates a chamber problem, and they'd likely respond by sending a replacement barrel for him to try.

None of the brass cases, federal and Win ruptured. The TV cases were more split that ruptured, unless it equates to the same thimg.