I currently have an AR10 .308 with a 16in barrel and a twist rate of 1:10. The optic is a Vortex Viper 4x16x44, however, I am struggling to find an ammo that it likes in terms of hunting rounds. I have put 150 grain, 175 grain, and 180 grain rounds through it and cannot seem to get a decent grouping at all, currently the best grouping ive gotten is 3 inches at 100 yards, which isn't great. Any input would be great from y'all on ammo opinions.

try some 168's

Put a better trigger in it.

Check your scope/mount tightness. Clean the barrel of copper. Try a 168.

It's either a really cheap gun or there's something wrong, and I suspect the latter. What is your shooting set-up like? 3" off the hood of the truck wouldn't surprise me, 3" off bags would be concerning.

1. Clean the hell out of it and foul it back in (5-10 shots).
2. Check the weight of the trigger but if it's under 5lbs it should still shoot at 100 yds.
3. Make sure everything is tight.

You didn't mention which ammo you were shooting. If those are quality brands, then you're ok. If they're Joe Bob special $7.99/box, get something better.

If after all that it's still not shooting, swap the scope.

I bought a Diamondback AR10 308 w/ 18" barrel. Had the same trouble....3-4" @ 100y regardless of what I fed it. I even broke down and bought a box of Federal Gold Metal Match 168's....supposedly, if a 308 won't shoot them then something is wrong. Well, something was wrong. I called Diamondback and explained everything I had done, they sent me a new barrel. I got it and put it on....now it'll shoot groups that you can cover with a quarter at 100y.

Point being...don't be afraid to call and talk to the manufacturer.

Shooting prone off the bipod, I've just been shooting some core lockts and super x rounds through it, as this will be primarily a pig gun. Going to buy a box of Nosler or Hornady's go higher end to see if that solves the issue

Interesting you say that, this is a diamondback, which i purchased earlier this year. I wish I had shot it sooner so I could see if the barrel is actually the issue. How long did the process take between sending the barrel in and receiving a new one?

I have a DPMS that was shooting bad. Installed a Timney trigger helped as much as anything. Shoots blue box Federal about an inch groups now. 150 grain is what I'm shooting.

Another tip, lose the bipod for now. Shoot it off sand bags and not on the bipod. The bipod can induce stress into the rifle to cause accuracy issues. Once you establish how it shoots off bags, then go to a bipod. When you switch brands of ammo, clean it and foul it back in. If you are feeding a lower priced AR lower priced ammo, don't expect bench rest accuracy. If you want some match grade ammo, give me a buzz. There are certain tricks to help an AR run better. If I'm loading 308 Win ammo and I know it's for an AR, I load the ammo different than I do for a bolt gun. Yes, it makes a difference.

Also, it's not the weight of the bullet that the rifle likes or dislikes. It's the load used with that bullet that the rifle likes or dislikes., So, saying that your rifle won't shoot a certain weight bullet is false (generally). Selecting a tangent ogive bullet that is appropriate for a AR will also help.

They were great to deal with. I had the barrel with a prepaid to send the old one back to them (it was the stainless barrel, had it been the chromoly they acted like they wouldn't have wanted that back) in less than a week. I swapped it and started load work up again.




I agree with this to a point. 1 - weight of bullet is not relevant, it's more type/style/brand/etc 2 - In my experience life it too short to force feed a barrel a bullet that you have to jump through hoops to get to shoot. You can also get to a point where you are throwing good money after bad. (been there done that...got a 1k 130 Berger Match 6.5 bullets that are useless to me to prove it

In short what I'm disagreeing about is not every rifle will shoot every bullet....sometimes it's not the load it's just that barrel isn't jiving with that bullet. Ex - you get a "fat" or "slim" bullet in a "tight" or "loose" bore and they just won't work....Lapua Scenar 105's in a .237 bore is typically not a good recipe for success.

assuming you rule out everything else..
I have an extra barrel, Wilson Combat 18" 308, fluted, black I would let go of for 150
it's a great shooting barrel with a variety of ammo. Just switched it out to a 20' 6mm Creedmoor

I agree Judd. That's why I put (generally). There are some situations where you come across like that.

Just got it out with some quality 165g Ballistic Tipped Nosler and happened to be just what it likes 1/2 moa at 100

Well that’s a great group for a nice bolt rifle, let alone an AR. You should be happy as a lark!

I'm having trouble grasping this. If the hand guard is free floating I don't know how a bipod would cause stress.

Even with e free float, it's still attached to the barrel at the barrel nut.edit. Nevermind it would have the same effect s the bags. Bags are more stable than most bipods.