First "Precision" AR Build - 5.56

[MikeMcC]

Gents,

I've built 4 ARs previously for various roles, but never built one for long range precision shooting. I've got access to a 1000 yard range, and have been shooting bolt guns there for years, but just never had the interest to try anything out of an AR platform. Fast forward to earlier this year, I found a spare YHM lower that I'd put in the back of the closet and forgotten about; I figured I'd give the long-range AR project a try.

Below shows the initial load testing at 100 yards; it seems to like 24grs of varget behind the 77gr Sierra TMK. This is a good thing because I bought 500 of them out of the gate, hoping I could get them to shoot. This was also my first real time shooting prone from a bipod (I'm a concrete bench and bulls bag guy for bolt guns). I'm going to re-shoot off a bench, then try different primers, and applying a very light taper crimp to see if I can shrink the group sizes anymore.

I will need to chronograph the load once I get something I'm happy with, but I'm hoping I can squeeze 2750 out because that should still leave me supersonic at 1000 yards. If it's relegated to a 900 yards and in rifle, that's fine too, but 1k would be fun.

Edit: The rifle itself is done, but I also picked up a "Tactical Brass Recovery" brass catcher that mounts to a keymod picatinny rail section. I plan to give this rifle the same treatment I do my bolt guns, so I don't want to be throwing neckturned/weighed/mathced brass all over the place.

http://i209.photobucket.com/albums/bb35/MikeMcCa/Pic3_zpscqqihhew.jpg (http://s209.photobucket.com/user/MikeMcCa/media/Pic3_zpscqqihhew.jpg.html)
http://i209.photobucket.com/albums/bb35/MikeMcCa/Pic4_zpslldlgef7.jpg (http://s209.photobucket.com/user/MikeMcCa/media/Pic4_zpslldlgef7.jpg.html)
http://i209.photobucket.com/albums/bb35/MikeMcCa/Pic1_zpsx795il3e.jpg (http://s209.photobucket.com/user/MikeMcCa/media/Pic1_zpsx795il3e.jpg.html)
http://i209.photobucket.com/albums/bb35/MikeMcCa/Pic2_zpsckg2l3fp.jpg (http://s209.photobucket.com/user/MikeMcCa/media/Pic2_zpsckg2l3fp.jpg.html)

Upper:
Aero Precision Stripped Upper
Palmetto State Premium BCG
BCM Mod 4 charging handle
Larue Stealth 18" Barrel
SLR 14" Solo Rail
Atlas Bipod
SilencerCo Specwar/Omega Brake
SilencerCo Omega Suppressor
Cole-Tac Suppressor Cover
American Defense 30mm Mount
Vortex Viper PST 6-24x50 - MOA reticle

Lower:
YHM Stripped Lower
DMPS Lower Parts Kit
Timney 3lb trigger
Magpul PRS Stock
Rifle Buffer/Springco A2 spring
Magpul MOE Grip
Magpul MOE Trigger Guard

[Onyx Z]

I averaged exactly 2,700fps with that load and a magnum primer (CCI450). Give XBR a try for 77gr pills also. It gave me very similar performance and is a helluva lot easier to work with. Gives me consistent .5moa groups.

Also, there is no need to neck turn semi-auto brass since you should be full length sizing. And these guns are a lot more forgiving when it comes to handloading.

[MikeMcC]

I averaged exactly 2,700fps with that load and a magnum primer (CCI450). Give XBR a try for 77gr pills also. It gave me very similar performance and is a helluva lot easier to work with. Gives me consistent .5moa groups.

Also, there is no need to neck turn semi-auto brass since you should be full length sizing. And these guns are a lot more forgiving when it comes to handloading.

I would try 8028XBR but I've got 10lbs of Varget, and it seems to shoot well enough for the first time out of the gate; those left two groups are covered by a quarter. I'll pick some up in the future though; thanks for the tip! Regarding primers, I was using CCI-400 primers, but ordered some BR4s for my bolt 223. I may give them a shot to see if there's any change (not hoping for much). I may load 10 with a 450 primer just to see what happens.

Regarding neck turning, I am trying to keep the neck tension the same for all rounds, and to keep runout to a minimum, it's a one and done type deal so I don't mind. I know it's likely overkill on a gas gun, but at the least it makes me more confident that I've done everything I can to eliminate variables. Mind you I'm not taking off any major amount of material, just pulling the high spots out of the OD so when they're fired/resized I'll know they're uniform.

[rainman]

Nice build. I'm a fan of the SLR Ion rails...super easy mounting, nice fit/finish in my experience.


-Rainman

[P2000]

Looks like fun!

How much runout do you typically see in your reloads, and how are you measuring it?

That is a nice shooting area, I'm stuck on rocks and near cactus lol.

http://images.tapatalk-cdn.com/16/01/25/42080b047a2a599eb6c21b5c88168d9c.jpg

[MikeMcC]

P2000 - Nice Rig! It makes me jealous of your glass.

I'm measuring with a Neco Concentricity Gauge, and for this rifle I've so far seen what I would guess to average ~.003-.004" of runout on my prepped finished rounds. My varget loads (what I'm going to do further testing on) are compressed, so I can't use my redding comp seater; if so I could probably get that lower. I'm relegated to a standard redding seater for now.

Edited to add: I honestly don't know how much of an impact shooting rounds without all this prep would have, but as I mentioned above, it's just best practice in the bolt world, and it gives me confidence that any "misses" or "fliers" are a result of me, and not so much my ammo prep process.

Regarding my shooting area, it's my families ranch. I managed to find a pasture that hadn't been grazed in a few months and it was full of what was once lush grass. Most of the time if I'm shooting out there, it's bellies in a pasture that's over-grazed and has more insects on me than I'd prefer. If I'm going to do more prone shooting, I probably need to invest in a decent shooting mat.

[SeriousStudent]

Nice work.

I do have to admit, I chuckled when I read about how a mislaid lower turned into an entire rifle. I found an old Noveske Gen 1 stripped lower in the safe, and that turned into a Recce build for me.

Please keep us in the loop regarding your load data. I've ordered some LC brass and have a bunch of the 77 SMK's myself. Fortunately, I live real close to a Cabela's with plenty of rifle powder to experiment with.

[P2000]

Thanks for the info, that runout is in the same ballpark as my reloads, and the Neco Gauge is similar to what I have.

I put some 77gr TMK bullets on my concentricity gauge, and noticed that the green tip is not always concentric to the bullet. Some of them wobble quite a bit, easily seen by the eye. Next time I hit the desert I am going to try and see if it matters. My theory is that when the tip is not concentric it may cause more drag, and lower impacts.

You have a nice rifle, I'm interested in your results once you work up a load that you like.

[HKGuns]

Nice Truck!

[FatedFrenzy]

Beautiful piece. Love the look of the PRS stock, wish they weren't so heavy. I usually go with the Luth-Ar because of that.

[Stengun]

Howdy,

Nice setup!

I was kinda surprised that you went with an 18" barrel for a long range AR.

I'm building a long range AR and I'm using a 24" barrel with should be good for another 120 - 150 feet per second faster at the muzzle.

I'll start a thread and post pics someday, maybe.

Speaking of forgotten "stuff".............

About this time last year I was digging through my junk and opened a box that contained a stripped lower ( pulling a blank on the name....edit: Stag Arms ) and a PSA lower kit. I used it to build a 10.5" barreled .300 Blackout.

Paul