I have a long range AR. I have a shilen select match, heavy profile, rifle length gas block, 1-8 twist, 20 inches, with a muzzle brake. It is a very accurate rifle. Around .75 MOA with Hornady 75 grain Match. I’ve had a couple of .5 MOA groups and a few .25 MOA with the same gun. I have taken it out to 750 yards consistently on a 10 inch plate, but I struggle to get past 750 with any kind of consistent accuracy. I have yet to hit an 800 yard plate with this rifle shooting 70s up to 77s. I think it’s doable, but I don’t think I’m capable with my current set up.
no had a Smith do it. There’s some stuff you do to ARs with the right amount of torque on the barrel nut and gas block alignment that help. I’m not sure if he did anything machining wise to the receiver. Correct AR work is out of my lane. I know how to slap them together, but AR smiths know the ins and outs to really get them to shoot.
Achieving accuracy with an AR is something that can be done. I would say that bullets above 70 grains do offer the BC for ELR of around 1000 but IMO the 223 case does not hold enough powder to accurately send it at that distance consistently with a velocity of well below supersonic at anything longer than 700 yards. 600 yards yes, all day.
For big bullets IMO a tighter twist would also run better. Something in the 7.7 - 7.0 range
Thanks 300Whisper and JMGamesniper1 for your replies. I am able to successfully run Berger 85.5's in my bolt gun so wonder if 8 twist would work in shorter 20" barrel and thinking around 2500-2650 fps for the heavier bullets.
I have a 6mm arc that I assembled myself. It is a half moa rifle every day of its life with factory 108gr eld-m. That round stays supersonic to like 1150y or so, (from memory).
If you want a thousand yard AR, that isn't going to be a problem, but I'd say that building that rifle in .223 is severely handicapping yourself. A 10mph wind is going to blow that thing a half mile off course. There are many better options as far as ar cartridges go..
I've built them for prairie dog rigs. I use thick wall "slick side" uppers, trued by squaring the front face. 24"-26" heavy bull Shilen match select, White Oak (Wilson) and Lilja barrels. Bag rider on the free float tube.
John at White Oak will build you a barrel or an upper with a matching bolt.
DPMS , back in the day. Aero, Spikes, PSA, Odin and several others make them (try Google). They are a little thicker than "normal" AR receivers and maybe a little more rigid. IDK if that makes a rifle more accurate, but I don't need the dust cover or forward assist on a bench gun.
One issue is that they don't fit well in a clamshell upper assembly block (if you are a builder). I keep the top/bottom receiver fixture for use on billet or slick side uppers.
Lapping the receiver where the barrel extension meets the receiver is one way (tool can be found at Brownells). Bedding the barrel extension to the receiver is another trick(not the same as bolt gun bedding). I have found watching your torque specs is way more importanter as long as you use quality components.
I have a rock river “long range” set up. It has an 20 inch, 8 twist but 75s seem to be it’s threshold for heavies. If you are planning on shooting 77+ I’d go with a 7 twist.
I bought a RRA Fred Eichler Predator in .223/5.56 Wyled chamber with an 16" 1:7 twist barrel a dozen years ago.I cleaned up the receiver lapped the barrel. I use it mainly for coyotes, but took it to South D for PDs. I would find a dog town and set up 400 yrds away with a 30round clip and have those little dogs flipping in the air. I shoot SGK 65gr for coyotes & 55gr SGK for PD and chucks on top of H4895 Lapua brass. Getting 0.30 MOA. It is real fun to shoot. I don't think I will ever sell it, my wife will probably shoot it after I am gone.