Home Forums Hunting & Shooting AR and Tactical Rifles 6ARC

Has anyone here built one? Thoughts?

My use would be shooting steel to 500 yards. But sometimes in a match the steel has to react (spin) and .223s struggle. I figure a 103grain at 2600 will make a huge difference over a 75 at 2400. My restrictions would be a small frame lower, factory ammo, with a muzzle velocity less than 3K.

I did for for my kid. Pretty badass rifle, shot really well IMO.

Using starline Grendel brass, resized. m4E1 upper/handguard. WC barrel.

Struggled with powders. Wasn’t willing to trade consistency/temp stability for what is actually a bunch of velocity. 8200xbr at 2450 was consistent but lever/CFE gets way more speed. The high end velocities folks talk about aren’t possible with varget or XBR.

Kid shot her buck in 100 deg weather hence the concern and use of the xbr.

Hoping the new Staball match fills the gap.

I keep thinking about one but not until I see some more brass popping up.


Should be an excellent coyote/deer cartridge.

I have one.
I have enough brass to last a long time.
It's not hard to make it out of 6.5 Grendel brass.
I'm getting 2675 fps with a 105gr bthp, and 29.5grs of leverevolution. Iirc, I was holding 4 mils to hit a plate at 850 yards.

Such a short barrel to be going that slow with a 75 in 223? 20 inch tubes should be able to hit 2750 really easy... and that should make a difference. You may be well under even 16 though.

A hornady 105 bthp at 2529 fps retains 747 foot pounds of energy at 500 yards, and drops 57.4 inches at 500, according to my notes.

Hornady 105s are probably capable of more but my particular 22 inch barrel did not like them pushed fast. Your mileage may vary.

Just double checked. I’m at 2450 with my 14.5, which is the longest I shoot anymore.

I built one for the son a few months back. He bought a Proof carbon barrel. Tried to talk him into a lesser expensive barrel, but he insisted on that one. I tried 103 ELD-X with both Lever and 2520. The 2520 shot better, but at a lower charge weight. I have not run those loads over a chrono yet. With a suppressor, it seems a lot quieter than a 223 AR.

He did shoot a buck with that rifle and it worked very well.

I never tried 103s as best I can remember but I had good luck with 108 ELDs.

4 mils at 850?

with what a 500 yard zero at 8000 feet in the summer

Yep, I put together a heavy 21" ARC and then, later a lightweight 18" ARC. With loads for both, I've landed right in that 29.2gr - 29.5gr LVR sweet spot with bullets 100 gr and over.

Gotta say, I really like the cartridge, especially in the lightweight 18" rifle, it's set up for hunting, but I've run the 21" out to 1,250 yds. It was sucking wind there, but was more convincing at 1k, and was hammering at 750. This cartridge predictably does well with longer gas systems, I have a RLGS on my 18" and a +2 on my 21", I think Proof uses +1 for their 18".

I've been shooting mine suppressed, and as someone else mentioned, the round seems unusually quiet when suppressed. Don't know what it is, but I've had several people walk up at the range and remark on how quiet those rifles are, maybe it's because they hit steel pretty hard and the mismatch between muzzle report and impact is what folks are hearing.

Here are the velocities I've chrono'd recently out of the 18"

95gr SST, 29.5gr LVR - 2,676 fps, 2,680 fps
100gr TGK, 29.3gr LVR - 2,676 fps, 2,665 fps
108gr ELDm, 29.3gr LVR - 2,650 fps, 2,634 fps

I started development with 90gr TGKs last trip and shot this spread, probably going to focus in the area around 30.5gr.
90gr TGK + LVR
30.4gr - 2,802 fps
30.7gr - 2,834 fps
31gr - 2,874 fps
31.3gr - 2,935 fps

18" w/lightweight X-Caliber barrel


Switched to a hunting scope and lighter can after some load development.


Have been able to pretty consistently source 108gr ELD factory, and the rifle seems to like it.

I built one shortly after Brownells had the Brownells labeled Faxson barrels in stock. It’s only a 1:8 twist, but it works ok. These barrels seem to be hit or miss, but I’ve had good luck with it. I do wish I would have waited and gotten a better and a little longer barrel though.
I’ve had my best accuracy from 95 gr. Bullets and Accurate 2520 and LVRevolution.

Thanks for posting what you're doing with this - it's an interesting round. I'd be interested in one in a bolt gun. Seems like a good, slippery, long range round with better barrel life than say a 6 Creed? Tho I know - barrels are made every day and to be shot out. lol.

Got a 700 LA laying around?

Not my cup of tea but I look for Ruger to have one in an American, whether Ranch or Predator.

I will probably build one for myself later this year. I have another 6mm CM to build first.

Anyone have experience with the Odin Works barrels? I see that they have 6 ARC, but no knowledge of any of their barrels. I do have their AGBs on some ARs.

My first 6mm ARC barrel is the 21" Odin, it hasn't been bad, groups 108gr ELD factory around 3/4", but it's such a pig, I probably wouldn't get it again. After shooting the round a bit and running it pretty far out, I liked the velocities I was getting with good bullet weights and figured it would make a nice hunting carbine cartridge, with a lighter barrel.

WC came out with their AR barrel at that point, I ordered one with RLGS but due to some kind of insanity they decided to cancel that version and only sell the MLGS version, which I wanted no part of on an 18" shooting 30gr of LVR/CFE suppressed.

All that to say, the Odin 21" isn't bad, but if you want something toteable, you'll have to look elsewhere and there aren't a whole lot of factory options. I wound up ordering my RLGS 18" lightweight contour from X-Caliber when they had a sale and it has been exactly what I was looking for, and pretty good price wise. I definitely would not get Odin's 18", as unless they've changed it it comes with a +2 gas system, and that's too much of a good thing, lots of complaints from owners trying to get them to run.

Proof was in on the SAAMI development of the 6mm ARC and offer a variety of chunky steel, or carbon barrels in the chambering. Faxon and BA offer barrels, but reviews on accuracy are mixed. I'd guess other makers have probably started offering the ARC since I was last looking.

Ndbowhunter,
I said "IIRC"...
Been since last year that I've been behind a rifle stock.
Will be a bit longer still too.
I'll have to check drop charts to come to present mind on what I was doing.
Oxycodone has a way to fog the mind, and not remember things too well.
Excuse me for saying iirc...

Thanks for the info. Guess I will pass on the Odin and keep an eye on the x-caliber barrels. Son’s Proof carbon with an AGB was easy to get running.

I notice that CLE has 6 ARC barrels.