Is it possible to build an AR that will do this?

[Keith Glasscock]

I've been playing with the idea of building (or having built) and AR rifle.

I'm thinking:

223 rem / 5.56x45 Nato
18" or 20" barrel
mid-range optics - like the Sightron 2.5-17.5
All up weight less than 10 lbs and dead reliable.

Now, the question:
Is it possible, better yet, likely that an AR can be built that will give me 10 shot groups of 1/2 MOA or less at 600 yards? Can it be done feeding from a magazine?

If possible, what should I be looking at/for? What works, what doesn't?

Thanks!

 

[people]

Keeping an AR under 10lbs with an optic is easier than ever. A thin tube like the a1 and a skeleton type stock make it easy to cut weight.

Handguards weigh less than a free float tube fft but will cost you in the accuracy depth. If you are going to baby it your fft can be shorter than what is standard. I personally like the jp kit plenty of grip and is thin.

Half out to 600 that is possible but you might be hard pressed to get that from a very light build. All my pd uppers have heavy tubes on them and no chance of making a 10lb limit unless you just measure the uppers.

 

[spclark]

Busdriver I think it's possible but with those specs closely paralleling what a typical CMP/NRA service rifle AR is built to (besides weight, stock choice and optics of course) that half-MOA goal is a significant challenge... even when the wind's not blowing.

@ 600 yards 1/2 MOA is a tad over 3" so your first criteria IMO ought to be bullet choice. Picking among those out there capable of this kind of potential, then feeding from a magazine reduces the possibles to one maybe two choices, neither of which are better than those that would require loading to a COAL longer than what'd fit in a 2.25" magazine length for optimum performance.

One MOA would be more realistic. Physics is hard to bargain with.

 

[flatlander]

In my experience, it's unrealistic to expect 1/2 MOA at 600yds out of any magazine fed 5.56/223 round out of any semi auto rifle in that weight range. I agree that 1 MOA is much more realistic, and have a couple of ARs that are capable of doing just that, with 1-7tw bbls & Nosler and Sierra 77BTHPs.

My 24"Krieger barreled AR15 rifle will shoot 77s into 1 MOA at 600 in good conditions, but with a 30mm Nikon 4-15x50 scope, it weighs about 12lbs. OTOH, I built myself an 18" SPR with a relatively inexpensive WOA SPR bbl w/mid-length gas system that's just barely capable of 1 MOA at 600 with 77s, and it weighs right at 10lbs with a 1" tube Weaver Super Slam 3-15x42 scope.

 

[Shynloco]

In my experience, it's unrealistic to expect 1/2 MOA at 600yds out of any magazine fed 5.56/223 round out of any semi auto rifle in that weight range. I agree that 1 MOA is much more realistic, and have a couple of ARs that are capable of doing just that, with 1-7tw bbls & Nosler and Sierra 77BTHPs.

I'd have to echo what Flatliner said. Of course, lots of $$$$$ helps increase your chances of better accuracy, but you are still fighting the inherent aspects of a magazine fed semi auto.. Just my .02 worth.

Alex

 

[BCoates]

In my experience, it's unrealistic to expect 1/2 MOA at 600yds out of any magazine fed 5.56/223 round out of any semi auto rifle in that weight range. I agree that 1 MOA is much more realistic, and have a couple of ARs that are capable of doing just that, with 1-7tw bbls & Nosler and Sierra 77BTHPs.

My 24"Krieger barreled AR15 rifle will shoot 77s into 1 MOA at 600 in good conditions, but with a 30mm Nikon 4-15x50 scope, it weighs about 12lbs. OTOH, I built myself an 18" SPR with a relatively inexpensive WOA SPR bbl w/mid-length gas system that's just barely capable of 1 MOA at 600 with 77s, and it weighs right at 10lbs with a 1" tube Weaver Super Slam 3-15x42 scope.

I agree with Flatlander. Less than MOA at distance is challenging to achieve with a mag fed AR. I would say that 1/2 MOA is near impossible.

What do you plan to use the rifle for?

 

[people]

Do not have so much free bore it will help out so much it is not funny on average. All my new tubes are set up for mag length ammunition.

 

[Keith Glasscock]

It is my idea of an all-around rifle for hunting critters (we have sage rats in Oregon), punching paper, and the occasional run and gun type match.

Sounds like the requisite accuracy is not likely. I was pretty sure it wasn't but thought I'd ask. Out of curiosity, if the weight was allowed to rise significantly, would that change the outcome?

Thanks to everyone who responded.

 

[acloco]

Believe it IS possible, but the rifle will be a little bit front heavy.

20" competition barrel, combined with an aluminum 8/9" free float tube, and the other lightweight or "weight savings" components listed above.

I WOULD use a billet upper - a little extra and better metal cannot hurt.

 

[spclark]

...if the weight was allowed to rise significantly, would that change the outcome?

No, I don't think so; for that kind of accuracy on a consistent basis you're still handicapped if you want to load no longer than 2.25" for magazine-fed rounds.

Now if you want to start spending $$ on an AR-10 chambered in 22-250 or similar then you might be able to achieve the goal you've set for this package!

 

[MrMajestic]

I believe with the barrel length and magazine restrictions you will have trouble staying above Transonic at 600 yards and may be another barrier. I have a 20"9tw Bull barrel that does 1/2 MOA at 200 yards with the Nosler 69 grain HPBT CC in front of N140 but I never ran it to 600. You have me wondering now, I will give it a try Friday to see how it does. ;D

 

[Dos XX]

I believe with the barrel length and magazine restrictions you will have trouble staying above Transonic at 600 yards and may be another barrier. I have a 20"9tw Bull barrel that does 1/2 MOA at 200 yards with the Nosler 69 grain HPBT CC in front of N140 but I never ran it to 600. You have me wondering now, I will give it a try Friday to see how it does. ;D

2600 fps with a 77gr SMK will keep you supersonic out past 600 yds. I think factory Fed GMM will do that in a 20" barrel, so it should be achievable with mag length hand loads.

 

[MrMajestic]

Transonic, Mach 1.2?

 

[chkunz]

Transonic, Mach 1.2?

I was not sure what your question is but transonic is considered Mach 0.8 to Mach 1.2.

 

[MrMajestic]

2600 fps with a 77gr SMK will keep you supersonic out past 600 yds.

Sorry, it was a question to Dos XX. He said super and I wanted to know if it stayed above Trans. This was my original concern with the OP.

 

[Dos XX]

JBM @ 2600 fps.

 

[MrMajestic]

Wish I had the twist to give them a try, Thanks

 

[Dos XX]

I shoot them out of an 8 twist 18" barrel in factory Fed GMM. I have shot them out to 1000 yds. I can make accurate hits at 600. Out past 800 or so, they start getting wonky.

I can make hits on big targets at 1000, but they are far from accurate that far out, but that system isn't designed for that distance.

 

[abishai]

answer to the OP - No . An AR 15 at 600 no matter the cost , or weight will not shoot 1/2 MOA 10 shot groups . To get what you want , you need a 5.5 g1 BC and 3000 FPS to start . 10 Xs in a row are the stuff of legend . It happens , I have seen it , I have done it . 6 s or bigger did it .

 

[savagedasher]

I don't know if AR 223 could do 10 shots at 300 yd with half min. With any normal conditions.
Marry Christmas Larry