Need more help with my AR accuracy in 223

[Viperdoc]

My AR, with a 1/9 Krieger barrel and Geissele trigger still won't shoot less than an inch, even off a bench rest. I have worked the ammo part to death: four kinds of bullets, four kinds of powders, three primers, neck turning, etc, but still no luck. Best ammo for consistency was with the Hornady 75 match bullets, with an SD down around 12, but still shot poorly.

Sierra 53MK, Berger 62, Sierra 69, and Hornady 75's were tried, along with TAC, H335, AA2520, and Varget, along with Remington 7 1/2, CCI SR and BR primers, all with new and once fired Lapua brass, primer pocket uniformed, full length resized, varied neck tensions, turned necks, chamfered necks, etc.

Don't think it's my trigger technique, since I can shoot easy 0.3 groups with my bolt target gun using the same rest, and a lot less effort in making ammo.

So, back to the rifle, which has a Nikon 8-32 scope mounted. Remounted scope, tightened everything, but no luck. Thinking of taking the scope off of the bolt gun (a Nightforce), and mounting it on the AR.

Other than seeing bad groups, are there any other ways to test the scope/mount combination? Everything seems to be pointing in this direction, unless the barrel is an unusually bad one. (also cleaned with Hoppe's 9, then JB paste, or Hoppe's bench rest copper remover, so probably not copper deposits).

Scope was previously mounted on a rail extension to improve eye relief, so I took the extension off and remounted scope with some new rings as well, and will try today. Other than switching scopes, are there any other ideas? Would like to see this rifle shoot less than 0.5 on a consistent basis.

Running out of ideas, but even though I am new to it, the experienced guys at the range all say the gun should be shooting better. Originally went with a Nikon scope because I have a bunch of their cameras and lenses, and they are top notch. However, the Nightforce is in another league, and of course the cost reflects this.

 

[navyrad8r]

Wow!!! i am at a loss too. maybe you need to shoot the cheapest components around (Ultramax remanufactured)? Your thorobread wont eat imported items. As a last ditch with the rifle, Go back to TAC/Varget...RL15/I4064- wolf magnum SR and make a few rounds up and jam them .010 in the lands for a few shots to see if the FB in the chamber is giving long of a jump. I shoot the crud out of Hornady's/ Bergers and love them. If you are shooting from the mag for the rapids that is one thing, but at least slow fire may give you an idea of what the rifle can do. Is there a chance the chamber was cut poorly? you could cast the chamber to be sure. After that i would have to agree with you that maybe the scope shuffle is in order. Maybe something is loose? i would even donate a handful berger/ JLK 70's to help solve your dilemma if you thought it would help. Good luck to you.

 

[Klong]

Who put the barrel and upper together? Be sure that the gas tube is not touching the barrel nut. Look to be sure that the crown is not damaged. Since you did not say anything about it, I assume the function is fine. Whqt case and primer are you using? Do you have any other guns that shoot your loads to 1/2"? How do you measure the powder?

 

[Klong]

Well I see you have another post going on this subject, so some of my questions were answered and some were not. If you have another scope, try it!

I assume the handgaurd has a float tube.What do your groups look like? Any pattern?

I have had many AR's and have never had one that would'nt shoot under 1"

 

[Viperdoc]

I think I finally have made major headway toward solving the inaccuracy problem: As mentioned, the scope was mounted on a rail extension, to provide enough eye relief. One of the guys at the range said that this arrangement, even though it looked solid, might be the culprit, since I had gone to every possible length to tune ammo.

Well, I had an extra set of scope rings, so took the rail off, and mounted the scope directly to the flat top.

Groups today, with only a short test, tightened to consistently under a half inch. This was with new Lapua brass, FL resized, with a neck bushing to 0.246, and CCI BR primers. Using both Varget as well as H335, groups were just around or under 1/2 inch. Larger groups were called as such, since it was also windy and raining as well (Sierra MK 69's).

My tests last week showed that AA2520 showed SD's of less than 20 with the 69 MK's, while Varget gave SD's of around 12 with the Hornady 75's. I am going to focus on tuning these combinations.

Anyway, it looks like I am finally on the way, although I probably have nearly 2000 rounds through the Krieger already. Even though this one is a 1/9, I think the next one might be a 1/8.

 

[navyrad8r]

viper,
save the TAC for some heavies in the 1:8 twist when you get there. i use ~24-25gr fo tac under 80 A-max and am quite happy at the 6 if i do my part.

 

[dan06]

Glad it is shooting for you now...One suggestion that worked well for me was bullet seating depth......I cut the front out of a mag and gained some OAL that would still function. This cut my groups from moa down to 1/2 moa with 60 gr sierra Hp you can try this pretty easy before you cut a mag by single loading to conduct your test.

 

[jonbearman]

You should retorque the barrel if the groups start opening up again.Another thing I do is when the crown is cut ,try it at high speed like 1500 rpms and have your snith use a small nose radius ceramic insert. It will look like a mirror and shoot great.

 

[cliffy]

Revert to Alliant ReLoder 10x powder and 55 grain Berger Varmint or Target fare. Revert may be the wrong word, since these critters create perfect fare for your rifle's twist. Alliant RL-15 may be too-slow burning for a short barrelled .223. Whilst RL-15 powder may well be the very best powder for most .308 Winchester loads, it could be the culprit regarding .223 Remington prowess of accuracy perfection. Remember that I experiment like crazy. S-L-O-W powders work best in long barrels with heavy bullets. RL-15 is a medium speed burner, and a great powder within its PROPER applications. Varget is also rather sluggish within many .223 Remington applications. RamShot X-Terminator powder works its magical velocity with 35 to 50 grain fare in .223 Remington loads. From 55 to 60 grain loads, I find RL-10x unbeatable for speed and accuracy, or count my chronograph in sudden error, time after time. Cliffy