Inaccurate and imprecise AA Grendel barrel.

[k1dude]

About 5 years ago, I bought a stripped upper and a 16" button rifled barrel and bolt from Alexander Arms. I promptly built up the AR with the intent of using it for deer and pig hunting.

Since I rarely hunt, the rifle sat in my safe unshot for the past 5 years. I finally have a deer hunting trip coming up, so I decided to dust off the Grendel AR, sight it in, and get it ready for the trip.

Unfortunately, it seems to have terrible accuracy and precision. I decided to start off with Wolf 120 gr FMJ to foul the barrel and begin the break-in. I wasn't impressed with the groups, but I attributed that to the cheap Wolf ammo. Once I thought I had it sighted in, I switched to Hornady 123 gr SST's for some fine tuning since that will be the round I'll hunt with.

The best I could do with the SST's was about 4 MOA. At least the group was centered around the POA. So I decided to try 120 gr Hornady AMAX to see if my accuracy and precision improved. The AMAX shot about 3 MOA, but it was 3 inches low and right.

So I tried some Wolf 123 gr SP's. They were about 5 MOA and were 5 inches high and right. I went back to the original Wolf 120 gr FMJ, and they shot 5 MOA and were 4 inches right.

I went home scratching my head. It was the worst performing AR I've ever built.

I went back to the range a few days later with my sled to make sure I wasn't the problem. I basically duplicated the shooting performance of my original outing. So the problem wasn't me. I asked a good friend to shoot it and his shooting confirmed once again the original findings.

I've always heard rave reviews of these AA Grendel barrels, so I'm at a loss to explain my results. I'm considering removing the AA flash hider to see if it's the problem. I also bought some AA 129 gr SST's to try. I'm still looking for some Wolf 100 gr to test also.

Does anyone else have any ideas what the problem could be?

I could tear it down and rebuild it as a last resort, but I'm not sure that would accomplish anything.

[rickOshay]

What sighting system are you using?

[BluntForceTrauma]

As ROS hints, with that kind of variability, my first thought is check scope and mount.

[rabiddawg]

I currently am having similar issues with my oldest 16" AA Grendel. I bought it from an individual who assumed it was un fired. Iirc he obtained it in a trade. The gun shot pretty good for about four years maybe 200 rds then my accuracy fell off too.

My barrel has no markings whatsoever so I am wondering what I may have. I've decided to buy a new AA 16". I put one on another upper and am very satisfied with it

As for blaming sighting system, I went through all that with mine. Sent scopes in for warranty, double checked crosshairs level and bought a $200 torque screw driver.

I will admit that the barrel yo upper tit was what I would call loose. You could slide them together freely. The smith that torqued the nut for me advised against bedding it with loctite. I did not want to disrespect him so we didn't bed it. That could be part of the problem but as I said the gun shot good for several seasons.

I too removed my flash hider to look at the crown. The consensus is the crown is fine.

It still shot eradically without the flash hider

[k1dude]

What sighting system are you using?

It's a brand new Vortex Viper 2.5-10x44 from MidwayUSA mounted with an Aero Precision Ultralight. It's all properly mounted up and torqued correctly and seems rock solid. I suppose the guts of the scope could be loose and the reticle could be moving around, but I doubt it. Because if that were the case, I couldn't have reproduced the original groups 2 more times days later.

[EPeterson]

Did you assemble it yourself? And if so, how confidant are you that it was assembled and torqued down properly? I had a Lilja 6.5 barrel that a LGS put on. After mediocre results at the range, I put the barrel back on using loctite and torqued it down to proper specs. It now shoots very well. That being said, my fist AA barrel had gouges cut into the rifling and I never got consistent accuracy till I replaced it with said Lilja barrel.
Here's the marks, the barrel came off a AA 6.5 Tactical upper.
[ATTACH=CONFIG]8153[/ATTACH]

[k1dude]

Did you assemble it yourself? And if so, how confidant are you that it was assembled and torqued down properly? I had a Lilja 6.5 barrel that a LGS put on. After mediocre results at the range, I put the barrel back on using loctite and torqued it down to proper specs. It now shoots very well. That being said, my fist AA barrel had gouges cut into the rifling and I never got consistent accuracy till I replaced it with said Lilja barrel.
Here's the marks, the barrel came off a AA 6.5 Tactical upper.
[ATTACH=CONFIG]8153[/ATTACH]

I assembled the upper myself and had to torque it to 60 to time the nut to align with the gas tube. So it's nice and snug.

After seeing your AA barrel, I'm thinking I should disassemble the upper to inspect the barrel closely. I admit I didn't inspect it closely before assembling it.

Perhaps I should get a new and better barrel ordered regardless.

[VASCAR2]

Bill Alexander shows up on this forum from time to time and seems concerned about having satified customers. Bill has even helped other forum members with products not sold by AA. If you see a problem with the barrel after removal I suggest you call AA and describe your circumstances with this particular barrel. It can't hurt to give them a call before you decide to get a different barrel.

[k1dude]

I had already contacted AA about a month before I posted here. They were of little help because they rightfully pointed out there was little they could diagnose over email. I fear I'm just going to have to disassemble the upper. If there's no obviously visible problem, I'm not sure what I'll do other than order another barrel. Especially since I don't have a bore scope.

[Fredman]

If scope and mounts are fine, I would check the barrel to receiver fit. I just installed my new Faxon barrel, and the fit was so nice I almost needed a hammer! Try loctite.

[sneaky one]

Use the surface insensitive version- Permatex makes one also. Just keep unraveling the mystery.

I sent 1 upper receiver to 6.5 Whelon to have the frontal edge squared- Glad I did- it, before I built it,, was off quite a bit. It was an Rguns unit, from a trade I did- ski. Shoots bugholes now.

Re check everything . I watched a pal shoot groups like that at 60 yds. He had a 30mm scope mount CRANKED down HARD on a 25.4mm=== 1" scope. Cardboad- paper wedges too. Good grief.

[Klem]

Gluing your barrel is not the issue.

Without wanting to get into a debate over whether gluing or greasing the barrel into the receiver is the way to go consistent groups of 1MOA or less without gluing is normal for a quality barrel. 1.5-2MOA for an average barrel. I doubt whether the barrel/receiver join is the reason... unless the barrel nut is missing!

More likely scope, mounts, ammunition or a blown-out barrel. But it will have to be almost smooth bore for 4MOA (especially if you are using a scope). I have seen blown-out barrels still shooting 3MOA with iron sights after 10's of thousands of rounds, including plenty of full-auto abuse. Just saying, it could be the bore but unlikely.

[LR1955]

Guys:

I bet it is the barrel and no amount of inspection or tinkering will fix it or even find the problem. Unmarked barrel when he bought it means a Shaw or another hunting grade barrel. Some shoot just fine, others don't. That's why when asked, most people on the forum will say that the single most important part a person needs to buy is a high end barrel. Then it needs to be installed properly. You can get away with a economy upper or lower, service grade trigger, standard GI bolt and carrier group, but you won't get by with a poor barrel.

If I had done everything that was done with that AR and it still did not shoot well, I would buy a high end barrel and put it on. If a person wants to save a hundred bucks and go cheap on the barrel, he is taking a chance that need not be taken.

LR55

[k1dude]

Guys:

I bet it is the barrel and no amount of inspection or tinkering will fix it or even find the problem. Unmarked barrel when he bought it means a Shaw or another hunting grade barrel. Some shoot just fine, others don't.

If I had done everything that was done with that AR and it still did not shoot well, I would buy a high end barrel and put it on. If a person wants to save a hundred bucks and go cheap on the barrel, he is taking a chance that need not be taken.

LR55

You're probably right. IIRC, when I bought the barrel, people on this site were arguing if the barrels were made by Satern, Shaw, or Shilen. But everyone seemed to be very happy with the accuracy and precision with all of the above.

That was back when everything gun related was sold out everywhere. I couldn't get a response from AA if my life depended on it. They weren't answering calls or emails back then. So I never found out who made the barrel.

Is there anyone making a quality lightweight barrel for hunting? It seems there's lots of good barrels out there, but weight doesn't seem to be a concern from the producers I've investigated.

[rabiddawg]

Is there anyone making a quality lightweight barrel for hunting? It seems there's lots of good barrels out there, but weight doesn't seem to be a concern from the producers I've investigated.

You may not consider them but I bought the stainless 16" fluted barrel from AA. Ordered it in August and had it in 3 weeks. I am very pleased with how it shoots.

I called them last week. They answered and explained to me how to order another without using a credit card/debit card. I'm hiding the next one from my wife. How's that for service?

As someone mentioned above, BillA posts here occasionally and has been great in offering to help guys with issues that imo were not his responsibility to fix.

I'm pleased with everything AA and will stick with them.

[1075 tech]

+1 on the AA fluted stainless. Bought mine last year before they got slammed with orders. Had it in less than a week. Shoots under 1MOA with SST's for me. I did square the upper and bed the barrel.