I am considering buying a Grendel off a friend. He let me borrow it to test drive and we can't get it to hit for crap. Like 1.25" is the absolute best 100 yard 3 shot group we've gotten and most groups are between 2" and 3". It's got a guiysell(wow that's a hard brand to spell...) trigger and we've been shooting bagged on a bench.

Here's what I know about the gun. He bought the upper from Alexander Arms and thinks the chamber was killed wrong. When ejecting a live shell the bullet would sometimes stay in the chamber so he'd get a mag full of gunpowder. He sent it to Specialized Dynamics in Arizona. That guy specializes in varmint guns. He couldn't get it to behave so he rebarrelled it. The new barrel is 18" with a 1x9 twist. That was a couple years ago and it's been a safe queen since.

We couldn't get it to hit so we called AA. after talking about a lot of different possibilities they said the barrel doesn't have a fast enough twist. 1x9 is fine for a 20" or longer barrel but for 18" or under, they said they use 1x7.5. We are shooting factory 123 grain a max and hand loaded 129 grain sst.

We tried heating up our hand loads but it looks like the bullets just won't stabilize. Maybe with a lighter bullet it would shoot better? I don't want to go lighter though as this is going to be a night hog hunting gun.

So, anything else I should try? Anything short of rebarrelling that can be done?

my advice: don't buy.

I havent heard great things about AA, ive seen more stories of people with problems with them than good stories. If its had problems that haven't been fixed in this long, I would avoid it. Just my .02

[This message has been edited by Agfan2013 (edited 10/11/2012 9:30a).]

See what it does with lighter projectiles. If it's a hog hunting gun, going lighter won't be an issue.

Try out some 120 grains, even some 90's. I'm assuming there are some weights in between as well. If it's simply a barrel twist issue, you know your limitations. If it still won't shoot after tweaking the ammo, then you have a bad upper (which seems strange after everybody that has looked at it).

tx4guns is one of the resident experts on 6.5, so see if he chimes in.

They're FOS. My 18" with a 1:9 twist shoots half MOA with 129gr Hornadys. Don't buy it.

We loaded some 120's for it too and it didn't do any better.

I really don't want to go lighter. The whole reason for going to a 6.5 was to get a bigger, flatter shooting bullet.

I don't think there's anything else we can do to make it perform but I figured I'd ask here to make sure I wasn't missing anything.

Stupid question - are you sure it's not a sight or shooter issue?

A loose sight or a poorly made sight that cannot hold zero will produce the same results you are getting as well.

Based on tx4guns comment, doesn't sound like ammo is the problem. Could be a bad chamber or an out of spec barrel, or even a burr in the barrel. Lapping (either hand or fire lapping) the barrel may be something to look into.

I would say its a problem with that specific rifle. I have a mostly AA upper and it shoots lights out, it's not very finicky with anything I've fed it. The worst group I have shot is just over an inch and i have used 7 different bullets in my reloads. AA factory loaded ammo is very good as well. I have talked to many who have purchased complete rifles from AA and they love them. If you have bullets getting stuck, they are seated too far out. This can be dangerous and cause pressure problems.

Hmm. There's a night force on top right now. I hadn't considered that it might be the scope.

3 different people have shot it and everyone's results are very similar. I don't think its a shooter issue.

I think bullets that got stuck in the old chamber were factory, not hand loads. the gu selling it has been reloading for over 10 years and hand loads for precision long range rifle matches. Even if they were hand loads, I highly doubt he'd get his OAL wrong.

How is the NF mounted? If someone went all out on a NF but thought they could save on cheap rings or mount, that might be your problem.

How's the crown of the barrel look?

The rings are night force too.

The crown looks fine I think. I am no expert though. It's threaded for a suppressor. He gave me a birdcage flash hider but he couldn't find a crush washer so we've been shooting it without anything on the end of the barrel.

Sorry. It's a Leopold scope in nf rings. 6.5x20.

Here are the best pics of the crown I could manage.

I've never seen an AR barrel with a rounded recessed crown like that. I'd get it recrowned and see if that fixes it.

I'm going swap out the scope next week and see if that fixes my problems. If it doesn't, I'll pass on the gun. He is looking to get it sold sooner rather than later and I can't buy it hoping it's a relatively simple fix but ending up having to rebarrel it.

Thanks for all the help guys.

Tx4, depending on how this goes,I might be emailing you about an upper in a couple weeks.

The crown didn't look too bad, although it's not a normal crown for an AR.

As a last resort, have your buddy look into the David Tubbs Final Finish system. It's a fire lapping system that will smooth out any burrs in the bore that may be present. Works great, and you can choose between a factory loaded system or handloading your own.

I used it on my AR and it made a world of difference in the bore. If the gun is shooting like you say it is, this certainly can't hurt and has the potential to help.

http://www.davidtubb.com/final-finish-tms