New 6mm Advanced Rifle Cartridge

[5RWill]

I think anything shorter than 20” is giving up too much burn time/velocity for any of the smaller caliber grendel
Variants . My 20” 22 grendel test barrel yielded good velocity with 75 elds

Agreed 18” seems like it will be good for the ARC. My 12.5” grendel gets 2300fps with 123gr SST and considering the length of the gun to terminal performance i am not sure there is a better option for its intended purpose. For which is hog hunting but it is just incredibly versatile for a 12.5" gun.

 

[toygunner]

It all boils down to your the intended purpose of the rifle and personal preference.

 

[koshkin]

I am happy to see someone finally standardized one of the 6mm Grendel wildcats, although they way they did it, it will chamber quite nicely in the Grendel chamber. I bet a few people will do that.

I have been shooting 6.5Grendel pretty much since it came out and it is easily my favourite general purpose AR cartridge. Part of the reason for that is the fact that it does quite well out of a moderate length barrels. The sweetspot seems to be right around 18", although 16" barrels work well too. My 18" barrel is technically a 264LBC chamber, not that it matters much. I am getting about 2520fps with Hornady factory 123gr loads.

I might build a 6mm ARC, but I will wait until there are some reports of what velocities people are getting out of 16" or 18" barrells. That 2700fps number seems to be with a 24" tube. If it drops into the 2550fps range out of an 18" barrel, I'll stay with the 6.5.

Anyway, after the 224V introduction nonsense, I am not itching to be an early adopter for now.

ILya

 

[5RWill]

2700fps from a 20" barrel with a 108gr ELD M from the looks of it.. Not bad at all. 18" is going to be perfect for a SPR that is maneuverable. I was thinking i was going to go Valkryie but proof and a mk5 with this little cartridge would be a very nice SPR.

 

[smg1231]

Barrett just posted this:

𝗕𝗔𝗥𝗥𝗘𝗧𝗧 𝗔𝗡𝗡𝗢𝗨𝗡𝗖𝗘𝗦 𝗦𝗛𝗜𝗣𝗠𝗘𝗡𝗧 𝗢𝗙 𝟲𝗠𝗠 𝗔𝗥𝗖 𝗥𝗜𝗙𝗟𝗘𝗦 𝗧𝗢 𝗨.𝗦. 𝗗𝗢𝗗

Barrett Firearms Manufacturing, Inc. is pleased to announce that it has partnered with Hornady Manufacturing to chamber the REC7 rifle series in the new 6mm ARC offering. The first production run of these rifles has already been delivered on time to the United States Department of Defense, fulfilling a contract that was awarded to Barrett late last year.

The combination of the proven REC7 DI gas system and the potent 6mm ARC cartridge creates a product that is consistently accurate and easy to shoot. Carrying 24 rounds in the magazine, the 106 gr. ELD Match bullets leave the 18” Proof Research match grade stainless steel or carbon fiber barrel at over 2650 fps. This easily gives the rifle supersonic capabilities past 1000 yards.

Barrett anticipates these rifles will be available to the US commercial market after all US Military deliveries have been completed.

 

[koshkin]

2700fps from a 20" barrel with a 108gr ELD M from the looks of it.. Not bad at all. 18" is going to be perfect for a SPR that is maneuverable. I was thinking i was going to go Valkryie but proof and a mk5 with this little cartridge would be a very nice SPR.

I have not yet seen an ammo introduction where the manufacturers were not either mistaken about velocity or lying about velocity or paying some gunwriter to lie about velocity. And that's before we get to them saying nonsense about accuracy, barrel life, terminal ballistics, etc. I think I already saw somewhere that 6mm ARC offers better external ballistics and terminal ballistics than 308.

Best examples are 6.8SPC and 224V, but there are plenty more.

Once factory ammo is reasonable available and well explored, we'll see. I am not buying anything off of media blitzes with hand picked and hand made ammo. It is not uncommon for early hand picked loads to be running at higher pressure for better PR.

Now, given what we know about all the 6mm Grendel wildcats out there, I am much more hopeful about this cartridge than about most others I have seen introduced for a while, but I will still wait.

ILya

 

[5RWill]

I have not yet seen an ammo introduction where the manufacturers were not either mistaken about velocity or lying about velocity or paying some gunwriter to lie about velocity. And that's before we get to them saying nonsense about accuracy, barrel life, terminal ballistics, etc. I think I already saw somewhere that 6mm ARC offers better external ballistics and terminal ballistics than 308.

Best examples are 6.8SPC and 224V, but there are plenty more.

Once factory ammo is reasonable available and well explored, we'll see. I am not buying anything off of media blitzes with hand picked and hand made ammo. It is not uncommon for early hand picked loads to be running at higher pressure for better PR.

Now, given what we know about all the 6mm Grendel wildcats out there, I am much more hopeful about this cartridge than about most others I have seen introduced for a while, but I will still wait.

ILya

Agreed, i have my doubts but i hope i'm proven wrong. I would love for this thing to somehow retain moderate velocity down to short configs in decent a 6mm weight class.

 

[Foghornleghorn]

Just talked to Forster and the engineer said they are looking at producing dies for the 6mm Arc. He asked for my information to use as interest for production. Would be a good idea if we dropped em a line and let them know how many would buy.

 

[Triple D]

108’s will be in the 2620-2630 range from an 18” proof from what’s been shown so far.

 

[Gtscotty]

I have not yet seen an ammo introduction where the manufacturers were not either mistaken about velocity or lying about velocity or paying some gunwriter to lie about velocity. And that's before we get to them saying nonsense about accuracy, barrel life, terminal ballistics, etc. I think I already saw somewhere that 6mm ARC offers better external ballistics and terminal ballistics than 308.

Best examples are 6.8SPC and 224V, but there are plenty more.

Once factory ammo is reasonable available and well explored, we'll see. I am not buying anything off of media blitzes with hand picked and hand made ammo. It is not uncommon for early hand picked loads to be running at higher pressure for better PR.

Now, given what we know about all the 6mm Grendel wildcats out there, I am much more hopeful about this cartridge than about most others I have seen introduced for a while, but I will still wait.

ILya

You really think Hornady is paying him to straight up lie on video about the velocities he chrono'd in his 20" AR, complete with a picture of his Lab Radar screen? All to what? Convince people that they will get 50 fps more than reality? I don't think so.

The barrel, being on the nicer end and probably lapped etc. might well be faster than a basic BA barrel, but I really doubt he's lying and Photoshopping chrono velocities.

108gr ELDs @ 2,650+ fps out of an 18" barrel (Barrett press release) sounds really good for factory ammo to me. 123gr ELD factory averages 2,390 fps out of my 16" Grendel, and my accuracy handload for 73gr ELDs (much lower BC) is running ~2,700 fps out of my 18" .223 Wylde.

Edit: Just found the Barrett press release, it actually says "over 2,630 fps" instead of "over 2,650 fps", not really a material difference for my uses.

News - Barrett Firearms

news.barrett.net

 

[koshkin]

You really think Hornady is paying him to straight up lie on video about the velocities he chrono'd in his 20" AR, complete with a picture of his Lab Radar screen? All to what? Convince people that they will get 50 fps more than reality? I don't think so

The barrel, being on the nicer end, might well be lapped and faster than a basic BA barrel, but I really doubt he's lying and Photoshopping velocities.

108gr ELDs @ 2,650+ fps out of an 18" barrel (Barrett press release) sounds really good for factory ammo to me. 123gr ELD factory averages 2,390 fps out of my 16" Grendel, and my accuracy handload for 73gr ELDs (much lower BC) is running ~2,700 fps out of my 18" .223 Wylde.

I offered three options. You are looking at the last one.

I'd be very surprised if Tom is lying, but I would not be at all surprised if final production ammo turned out to be a bit different than the first batches of ammo used for the marketing push. It might not even be all that intentional: when you go into full production you have to stay further away from the hairy edge of performance.

There is already a marketing blurb that they have a "special" bullet with special construction better terminal ballistics than the 308. There is some word sophistry there, but they are basically lying. Whatever special design bullet they have, if they apply the same design to a larger bullet, it will have better terminal ballistics. Only professional marketing can make these claims with a straight face (half of my job is marketing; ask me how I know). So why would I assume they are not lying somewhere else?

If it can reliably push 108gr ELDs out of an 18" barrel with factory ammo at 2650fps, I will most certainly build a rifle in 6mm ARC.

ILya

 

[Ledzep]

108gr ballpark numbers for those who are curious...

12" : 2350
14": 2450
16": 2525
18": 2600
20": 2650

+/- 75fps barrel to barrel variance, etc.

 

[Kartman]

Sounds cool. WIll be interesting to see how it develops

 

[Bantam1]

What I was told at SHOT from my contact at Hornady was the development was done with Proof and in an 18" barrel for the DOD request. They may get a special round for their needs. I will ask my contact eventually but he is pretty busy given the current ammo demand, CV absentees and new product releases. I try to leave him alone as much as I can because he's busy working on new stuff. He mentioned they really focused on barrel life and terminal/barrier performance at the specified ranges that the DOD requested. I'm sure you could squeeze more hand loading for it.

I posted the relevant data a while back for velocity with the factory loaded ammo. I was immediately interested when we spoke at SHOT. He offered to loan me the chamber reamer they had made for a build a while back, but I just didn't have the extra cash to spend to build a new upper. Maybe later this year or next year. It sucks being a "poor" in CA.

 

[joffe]

LAN TAC has posted velocity and energy charts of 18" as well as 14.5" barrels along with their marketing.

 

[joffe]

There is already a marketing blurb that they have a "special" bullet with special construction better terminal ballistics than the 308. There is some word sophistry there, but they are basically lying. Whatever special design bullet they have, if they apply the same design to a larger bullet, it will have better terminal ballistics.

Sure, but it would be a .30 caliber bullet with the same characteristics, which in turn would mean that it would be too long and too heavy to be effectively used in a .308 Winchester chambering. It would be a bullet for .300 NM or something else in that ballpark.

It's an apples to oranges comparison, to be sure, but it's not lying. It is also the chambering that this new cartridge is supposed to supplant for the DOD contract they were developing it for, so you can't say it isn't relevant.

 

[steve123]

Marketing - like what the Co's first advertised the 224 Valkyrie to achieve?! Then they figured out that loading it down was better than blown primers and ruined 1x brass.
I helped a guy experimenting with a wildcat that is basically a 224V, and the developer found out that at the time only SSA brass would handle higher pressures longer than the rest of the brands, so how strong the brass is makes a big difference.

Hornady brass is what it is and it's not Lapua, that's for sure.

I've pushed 6mmART40 to 2920 fps with 105's before in a 26" barrel for 1 firing, slowed it down to 2875 fps afterwards, and Lapua brass held up for 6-7 firings. Twice that amount slowed down to 2740 fps.

I won't say yay or nay at this point but Hornady better use strong brass and the perfect burn rate of powder.

 

[M4guru]

I hunted some with a 6ARC AR earlier this year. DOD spec Proof 18" barrel and Hornday 108 ELD-M. It was accurate and extremely soft-shooting.

Mags are the current issue, 6.5G mags are pretty bad all around and that's what is available currently.

Got this javelina at just over 400 yards. I didn't cut it open to see the damage, but it sure dropped it in it's tracks.

 

[koshkin]

Sure, but it would be a .30 caliber bullet with the same characteristics, which in turn would mean that it would be too long and too heavy to be effectively used in a .308 Winchester chambering. It would be a bullet for .300 NM or something else in that ballpark.

It's an apples to oranges comparison, to be sure, but it's not lying. It is also the chambering that this new cartridge is supposed to supplant for the DOD contract they were developing it for, so you can't say it isn't relevant.

The statement that terminal ballistics are equal or better than the 308 is straight up lying.

If they said that the terminal ballistics of their special 6mm bullet are better than 147gr FMJ 308, I would be totally on board with that. The blanket statement is full of manure.

As far as the overall chambering goes, I am very much onboard with what they are trying to do and I hope this works as well as they claim. I do not like large frame semi-autos. That's how I ended up with the Grendel in the first place.

ILya

 

[RTV]

I hunted some with a 6ARC AR earlier this year. DOD spec Proof 18" barrel and Hornday 108 ELD-M. It was accurate and extremely soft-shooting.

Mags are the current issue, 6.5G mags are pretty bad all around and that's what is available currently.

Got this javelina at just over 400 yards. I didn't cut it open to see the damage, but it sure dropped it in it's tracks.

I agree mags are the current problem... makes me wonder what mags the DOD is using and if they have found a solution

 

[Gtscotty]

I agree mags are the current problem... makes me wonder what mags the DOD is using and if they have found a solution

The Barrett press release says 24rd mags, and the mag in the photo looks E-Lander-ish. I've been using ASC 10 and 15 round mags with no problems, I didn't realize folks were having so many problems with the other brands, lucky I tried them first I suppose.

 

[lennyo3034]

I can't get ASC mags to feed for shit with my Grendel. Hoping Elander is better.

 

[bfk4lyfe]

I can't get ASC mags to feed for shit with my Grendel. Hoping Elander is better.

For what its worth, I've had the opposite results. Mine are 10 rounders and I don't know if that has something to do with it, but they ASC feels like it might hold more (and seats on a closed bolt no problem) but my elanders are 9 rounders at best.

 

[M4guru]

I believe they were using E-Landers. Regardless of the gun (Barrett makes a good one) none of the mags are duty-ready, especially if any particulate is introduced.

The magazine roulette you guys are seeing play out above is typical, they're very inconsistent from mag to mag and lot to lot.

 

[mason.ostrom]

I’ve had good results with ASC mags in both a 6.5 grendel and 6MM grendel.

 

[yellowfin]

I have an upper sitting around doing nothing that I'll swap this barrel onto. This is what I've been waiting for.

 

[Redfisher60]

Curious as to why Magpul never made 6.5 Grendel mags.

 

[Ledzep]

Curious as to why Magpul never made 6.5 Grendel mags.

There was a big push for it back in the mid 2000's. If I recall correctly Magpul didn't feel good about how thin the polymer would have to be to support the bigger diameter case body.

 

[toygunner]

Give the PRI mags a try . The ribs make the sides stronger and minimize flex . I use them in all the Grendel cased rounds along with 22 BR and 6GT

 

[sam4886]

Agree on PRI mags. No problems with mine.

I'll be first in line for a Howa mini 6ARC. I've got the 6 predator and think it would be tons of fun in a little Howa, but haven't gotten around to wanting a rebarreling project bad enough yet.

 

[Kamerad]

...you have to stay further away from the hairy edge of performance.

ILya

This is gold!

 

[Redfisher60]

Give the PRI mags a try . The ribs make the sides stronger and minimize flex . I use them in all the Grendel cased rounds along with 22 BR and 6GT

(PRI) they don't list a 6.5 Grendel mag, just 6.8, is it the same mag.

 

[toygunner]

Yes, the 6.8 mags

 

[vmpglenn]

Barrett used to have the only 30rd steel mag for 6.8SPC back in the day... I wonder if Barrett is also making mags for the DoD contract.

 

[5RWill]

108gr ballpark numbers for those who are curious...

12" : 2350
14": 2450
16": 2525
18": 2600
20": 2650

+/- 75fps barrel to barrel variance, etc.

think the 103 in a 12.5” would nearing 2450?

 

[Yondering]

The statement that terminal ballistics are equal or better than the 308 is straight up lying.

I'd like to see your source for these claims, otherwise it sure sounds like a false flag argument. We've seen charts posted showing higher velocity than the 308, but lower energy as any reasonably compentent shooter would expect. I've yet to see anything published about "terminal ballistics" compared to the 308 or anything else, so please post a source, otherwise let it go.

 

[Yondering]

I can't imagine that the ARC will sacrifice less than the Grendel when going short

It's the same case with a smaller bore - of course it will sacrifice more velocity when going to shorter barrels. That's how this stuff works; larger bores and heavier bullets are more efficient in short barrels.

 

[dlrflyer]

Perhaps with Barrett involved, they could develop a 6 ARC mag. Their 6.8 mag is quality, even if shorter than handloaders prefer.

 

[Ledzep]

think the 103 in a 12.5” would nearing 2450?

I could believe 2400 with a warm load, maybe a bit faster with a fast barrel. I haven't seen testing results that say as much yet, though.

I'm not condoning it but I suspect you'll see velocities that exceed the factory ammo because people who reload mostly rely on visual cues on the brass/primer which won't show up until much higher chamber pressures than what's recommended for the bolt thrust with a Grendel bolt.

 

[levi8599]

I’ve been running a 243lbc for a couple years now and I run 2810fps with a 95gr tmk and 28.6gr of 8208

 

[Gtscotty]

It's the same case with a smaller bore - of course it will sacrifice more velocity when going to shorter barrels. That's how this stuff works; larger bores and heavier bullets are more efficient in short barrels.

Obviously, that's why I wrote that.... What's your point?

 

[Gtscotty]

I could believe 2400 with a warm load, maybe a bit faster with a fast barrel. I haven't seen testing results that say as much yet, though.

I'm not condoning it but I suspect you'll see velocities that exceed the factory ammo because people who reload mostly rely on visual cues on the brass/primer which won't show up until much higher chamber pressures than what's recommended for the bolt thrust with a Grendel bolt.

Which is also why you see some really balls out loads being tossed around for the 6.5 Grendel, when factory ammo and book loads are usually a bit more sedate velocity wise.

 

[5RWill]

I could believe 2400 with a warm load, maybe a bit faster with a fast barrel. I haven't seen testing results that say as much yet, though.

I'm not condoning it but I suspect you'll see velocities that exceed the factory ammo because people who reload mostly rely on visual cues on the brass/primer which won't show up until much higher chamber pressures than what's recommended for the bolt thrust with a Grendel bolt.

I see that might be very tempting. I’m getting right at 2300 with a 123gr sst and 8208 out of my 6.5 Grendel. But it was crushing case mouths so i assumed it was over pressured. Haven’t reloaded much with the semis.

 

[Nimothy]

I have not yet seen an ammo introduction where the manufacturers were not either mistaken about velocity or lying about velocity or paying some gunwriter to lie about velocity. And that's before we get to them saying nonsense about accuracy, barrel life, terminal ballistics, etc. I think I already saw somewhere that 6mm ARC offers better external ballistics and terminal ballistics than 308.

Best examples are 6.8SPC and 224V, but there are plenty more.

Once factory ammo is reasonable available and well explored, we'll see. I am not buying anything off of media blitzes with hand picked and hand made ammo. It is not uncommon for early hand picked loads to be running at higher pressure for better PR.

Now, given what we know about all the 6mm Grendel wildcats out there, I am much more hopeful about this cartridge than about most others I have seen introduced for a while, but I will still wait.

ILya

+1 2700 out of a 18” seems very unlikely.

 

[Ndbowhunter]

My accuracy node with a 243win 20” 7 twist with 108’s and h4350 was only 2860.

it bang flopped everything it touched and absolutely was more in terms of terminal performance then what an 18” rifle length can do with 77gr tmk.

this is the cartridge i’ve been waiting for for years. Stoked to get a barrel and bolt and bang flop a truck full this fall.Gotta love credit card reloading.

 

[ajwcotton]

I've chambered a couple bartlein's at 22 inches and they were right around 2700 with 108's. One of them was in the hornady press release pics and videos. They were getting the same with it as the ammo I had.

 

[Nimothy]

I've chambered a couple bartlein's at 22 inches and they were right around 2700 with 108's. One of them was in the hornady press release pics and videos. They were getting the same with it as the ammo I had.

I was under the impression that Hornady was saying 2850 from an ar the one in the video was shorter than 22

 

[Ledzep]

+1 2700 out of a 18” seems very unlikely.

Not outside the realm of possibility, but on the top end for sure. In the "by the inch" test I saw 18" was around 2600fps. I have a Cz527 that is in 6 ARC with an 18" barrel that is also right around 2600fps with 108's.

Some barrels are faster than others. Like I said, 100fps isn't outright bogus but I wouldn't expect it to happen every time.

ETA: My rifle is a custom build, not saying CZ will be making factory 6 ARC's. They should, but I don't know if they will or not.

 

[darth_ritis]

I have not yet seen an ammo introduction where the manufacturers were not either mistaken about velocity or lying about velocity or paying some gunwriter to lie about velocity. And that's before we get to them saying nonsense about accuracy, barrel life, terminal ballistics, etc. I think I already saw somewhere that 6mm ARC offers better external ballistics and terminal ballistics than 308.

Best examples are 6.8SPC and 224V, but there are plenty more.

Dude, preach it! 25-45 Sharps and 22 Nosler and 22 Grendel fooled me. I'm done chasing AR15 cartridge snake oil, especially with handloads. 224V Hornady ammo has been true on velocity in my experience, to be fair. I'll keep my Valkyrie barrel, but I'm not in love with it.

I'm a solid Hornady fan these days, and have been thinking for years that a factory offered cartridge like 6mm AR (sorry Robert Whitley) is the ticket, so a new barrel in 6mm ARC is probably in my future, probably 22".

 

[Crabcore]

what is the brass life of this 6mmARC compared to 224V from an AR?