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New 6mm Advanced Rifle Cartridge

You don’t get faster bullets by reducing the vote and keeping the case and bullet weight the same.
 
What's the intel on this, is this based on Whitley's 6mm AR, or his 6mm AR Turbo 40?
 
It is what the 6.5g should have been, to be honest.

The 6.5 Grendel was designed around a 123 grain bullet to optimize its ballistics performance. Bill Alexander's intentions were also for it to appeal to the hunting market, hence the 123 grain bullet weight.
 
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Thanks, that's a shame, the T40 gives another 150fps, but still it's better than nothing.

I don’t think it is. Ihad a Lee Wells 6fatrat and shoot against turbo 40s. Fire forming the brass is a pain in the ass for no more of a return than you get. My 243lbc done just as well. Let alone the Lee wells whidden dies are over priced and I didn’t care for them from the start. If Hornady or whoever is releasing this cartridge can get someone like Peterson or Norma to make brass for it I think it will go over well. The 95 sierras are hard to beat when using the 6mm grendel variants. If you wantbetter performance over a 6mm predator or 243lbc with 95 grainers just move to the ar10 platform and run a 6xc creed or 243win.
 
I don’t think it is. Ihad a Lee Wells 6fatrat and shoot against turbo 40s. Fire forming the brass is a pain in the ass for no more of a return than you get. My 243lbc done just as well. Let alone the Lee wells whidden dies are over priced and I didn’t care for them from the start. If Hornady or whoever is releasing this cartridge can get someone like Peterson or Norma to make brass for it I think it will go over well. The 95 sierras are hard to beat when using the 6mm grendel variants. If you wantbetter performance over a 6mm predator or 243lbc with 95 grainers just move to the ar10 platform and run a 6xc creed or 243win.

Thanks, I have a GAP10 6CM that I use for PRS but like the idea of running a lighter AR15. I've used my JP 6.5 Grendel in matches with some good results, but have always fancied the 6mm variant. Agreed fire forming to the 40T would be a pain but apparently you still get fairly decent results even when fire forming. It would be nice to see Lapua getting on board as well.
 
Thanks, I have a GAP10 6CM that I use for PRS but like the idea of running a lighter AR15. I've used my JP 6.5 Grendel in matches with some good results, but have always fancied the 6mm variant. Agreed fire forming to the 40T would be a pain but apparently you still get fairly decent results even when fire forming. It would be nice to see Lapua getting on board as well.

A gunsmith in Wyoming built me a 6br on an ar15 platform. He just used a 458 socom bolt on it I believe. It shot well with the bartlien barrel. He builds dashers too. A dasher chambered ar15 with a Norma brass reamer and Norma Dasher brass maybe the ticket For running 105 and 107 grain bullets. I believe I used an elander mag with the front opened. It shot well and cycled. I still have his contact info if your interested.
 
A gunsmith in Wyoming built me a 6br on an ar15 platform. He just used a 458 socom bolt on it I believe. It shot well with the bartlien barrel. He builds dashers too. A dasher chambered ar15 with a Norma brass reamer and Norma Dasher brass maybe the ticket For running 105 and 107 grain bullets. I believe I used an elander mag with the front opened. It shot well and cycled. I still have his contact info if your interested.

Is he the guy that used to build 6 BRX uppers? Do you have his name?
 
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Man, everytime I turn around there is a new caliber that I think I MUST have. I've been eyeballing a .243 LBC for a while, but seems the 6mmARC would have more/easier component availability if it ever makes it to production.

Honestly if component availability is your primary concern (rather than factory ammo), there's no disadvantage to the current 243 LBC and some of the other variants. It's just Grendel brass, there is no forming except the first pass in the reloading die necks it down from 6.5 to 6; you almost can't tell it's happening.

On the other hand, it'll be a while before you have anything but Hornady brass available for the 6 ARC, IMO. If you want to use Lapua, now you're pushing the shoulder back too (i.e. you should consider neck turning) vs just necking down.

I could be wrong, but I think the only reason Hornady shortened the shoulder on this cartridge .030" is to make it incompatible with the current wildcats. The cartridge doesn't need it for bullet base vs neck/shoulder junction reasons, and the reduced capacity only limits performance a little while not being enough difference to make it a lot more efficient. I understand why Hornady wouldn't want their ammo used in wildcat chambers for liability reasons, but guys shouldn't expect this to be a better performer than current options.
 
It’s certainly going to be a better target/match option than a 6.5grendel...but I’m hoping for the 22ARC!
Take a look at the 224 predator. Neck down 6.5 Grendel brass with a Single pass thrOugh the 224P sizing die and load...
 
How reliable are grendel magazines?
Seems that would be the only make or break factor as to if I will be picking this up.
 
Mine took a little bending, but once in the right spot, zero issues. Use mostly PRI mags.
 
Looks like someone is running ahead of the marketing embargo?


The Hornady 6ARC Round


Hornady Mfg® a leading ammunition manufacturer, provides world-class performance in a 6ARC factory- loaded cartridge. The high-performance, match-accurate round features an excellent cartridge-to- chamber relationship and shoots exceptionally well. The 6ARC is commercially available in 108gr ELD- MATCH, 105gr BTHP BLACK and 103gr ELD-X -Precision Hunter loads. The ELD-Match round boasts a G1.536BC.



6mm ARC Advanced Rifle Cartridge

Advanced.

Versatile.

Efficient.

Effective.

Tested, selected and fielded by a specialized group within the US DoD for its multi-purpose combat rifle program, the 6mm ARC is an extremely versatile cartridge that does everything much larger cartridges can, and everything that smaller cartridges can’t. Designed to meet the demanding needs of the world’s toughest critics, the 6mm ARC is a truly advanced cartridge capable of utilizing high BC, efficient 6mm bullets for unprecedented levels of performance from such a compact platform.



Advanced–Purpose built to achieve performance never before delivered from the AR-15 platform by providing the ultimate blend of system weight, performance and shootability.

Versatile-Equally at home in AR-15 platforms and short or micro action bolt guns and suitable for a variety of applications from personal defense, match shooting, hunting as well as military and law enforcement use.

Efficient –Balanced application of cartridge and chamber geometry & interface, propellant design and bullet selection for optimum performance and barrel life, the 6mm ARC has unmatched long- range performance from the AR-15 or micro action platform.

Effective–Excellent terminal performance from an assortment of bullet selections, for a variety of applications.

Accurate

–Features match accurate Hornady bullets that are held to the tightest tolerances in our test lab. Low recoil

-Utilizes an efficient propellant charge and bullet weight combination.

-Self-spot impacts on or off target to make rapid adjustments.

-Less felt recoil than larger short action based (308 Win family) cartridges.

Flexible

-Factory ammunition offerings in a variety of bullet styles may be complemented by the handloader who has a multitude of 6mm bullets to choose from for specialized applications from varmint and deer hunting to match shooting needs

81608 6mm ARC 108gr ELD-MATCH

Muzzle Velocity = 2750FPS with 24″ test bbl G1
BC = .536
SD = 261
Min Twist Rate = 1-8”

81604 6mm ARC 105gr BTHP BLACK

Muzzle Velocity = 2750FPS with 24″ test bbl G1
BC = .530
SD = 254
Min Twist Rate = 1-8″

81602 6mm ARC 103gr ELD-X -Precision Hunter

Muzzle Velocity = 2800 FPS with 24″ test bbl
G1 BC = .512
SD = 249
Min Twist Rate = 1-8
 
So I wonder if proof is going to start cranking out barrels for it? If so I’ll probably go ahead and get on the 6month wait lol. Looks like the proof will be a 7.5 twist I wonder if that will stabilize the 108s in a 16 or 18” barrel?
 
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I am going longer barrel ... maybe 22 or 24 in CF. Let's see what they offer. Open to recommendations on BCG and billet upper. All my stuff is Mega but they are no more ... and I'm not too interested in Zev.
 
So I wonder if proof is going to start cranking out barrels for it? If so I’ll probably go ahead and get on the 6month wait lol. Looks like the proof will be a 7.5 twist I wonder if that will stabilize the 108s in a 16 or 18” barrel?

8 twist will stabilize the 108s. You'll want 7.5 if you want to go any heavier.
 
I just bought a seekins upper and hand guard off the px, I guess that’s what I will use to make a 6arc. Maybe 22” would not be too ridiculous on an ar15
 
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The product intro is up:


First factory loads:



 
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How reliable are grendel magazines?
Seems that would be the only make or break factor as to if I will be picking this up.
ASC 10 rounders have been flawless. Elander mags are beautiful, but I've had a few hiccups with their 17 round mags. I haven't had any issues with the 10 round elanders, but haven't used them extensively.
 
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I don’t think I wanna throw money into a proof cf until I have played with one for a bit, I’m still gun shy from Valkyrie (although I waited on the valk to age a little and that proved to be wise). I may go with a button barrel maybe someone like keystone, etc.

looks good though hopefully it catches on.
 
I’m more curious on how it performs in shorter configurations. 22-24” ARs are bulky and weighty for the cartridges in the platform. If it post better results than a 12.5” grendel with a 123gr sst at 2300fps. I’ll be very interested.
 
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I’m more curious on how it performs in shorter configurations. 22-24” ARs are bulky and weighty for the cartridges in the platform. If it post better results than a 12.5” grendel with a 123gr sst at 2300fps. I’ll be very interested.


Eh, my Grendel is 16", but I'm much more interested in 18" to 20" for an ARC barrel, I think that length range will really be where it shines. I can't imagine that the ARC will sacrifice less than the Grendel when going short, but I suppose it does start out quite a bit faster with similar BC bullets.


Question ... does this run on a Grendel bolt or a 6.8? Putting the list together.

It's a 6mm Grendel variant with the shoulder pushed back ~30 thou, uses a Grendel bolt and Grendel mags. The SAAMI case drawing is on the first post.
 
Eh, my Grendel is 16", but I'm much more interested in 18" to 20" for an ARC barrel, I think that length range will really be where it shines. I can't imagine that the ARC will sacrifice less than the Grendel when going short, but I suppose it does start out quite a bit faster with similar BC bullets.

I think right now the Grendel will be impossible to beat in that config. I agree though i just told a buddy of mine i bet the 6mm ARC is going to be the go to SPR cartridge in an 18~20 inch config.
 
The PRI mags have ribs on the sides which seem to work the best. The ribs make the sides more ridged. I found with more than 5 22 BR or 6GT rounds in the other mags the sides will bulge. The PRI run flawless without any mods. As for the 22 or 6 mm in the grendel the ARC, Elander, or Alexander Arms mags are fine. If you are putting together your own upper, use the JP bolt. They last longer.
 
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Just put together a 6.5cm semi. Should have waited for this

Hornady doesnt fool around
 
Most everything anymore uses a type 2 bolt, but I’d check with your barrel mfg.
I only use the type 2 Jp bolts anymore when chambering / head spacing barrels
 
Well it’s official, the new product from Hornady is the arc. I got an ad from ballistic advantage today as well stating that they are doing a pre-order on arc barrels. Looks like there is a wide range of other companies supporting the ARC. Hornady listed APF Armory, Barrett, Brownells, Christensen, CMC Triggers, CMMG, GAP, Geissele, Howa, Lantac, Mossberg, NEMO, Noveske, Odin Works, Proof, Radical Firearms, Unitah, Wilson Combat as manufacturers of firearms chamber in the arc. I’ll be interested to see the howa and mossberg ARC bolt gun offerings.
 
Most everything anymore uses a type 2 bolt, but I’d check with your barrel mfg.
I only use the type 2 Jp bolts anymore when chambering / head spacing barrels

Exactly, the bolt for a type 1 chamber is just a 7.62x39 bolt. The type 2 and SAAMI chambers all fit the actual Grendel bolt, which the ARC will as well.

While BA has a pretty good track record on affordable, and very decent AR Barrels, I'm going to hold out for a Proof CF 20 or 22".

I'll be looking to shoot the 103gr ELD-X more than likely.

The ARC shows up as an option on Proof's website, but all I see for SS and CF barrel lengths right now, unless I'm missing something, is 16" and 18".
 
Exactly, the bolt for a type 1 chamber is just a 7.62x39 bolt. The type 2 and SAAMI chambers all fit the actual Grendel bolt, which the ARC will as well.



The ARC shows up as an option on Proof's website, but all I see for SS and CF barrel lengths right now, unless I'm missing something, is 16" and 18".

Hmmmm... It's not like those wouldn't work, but I really want to be up in the 20-22" suppressed for longer shots and keeping velocity up. It may not make that much difference, but still what I would prefer.

I'll wait a little bit to see what's happening anyhow. I haven't seen brass or dies showing in stock as of yet. I'm not really interested in factory ammo.
 
Is 20-25 fps per inch a good ballpark velocity drop from the 24" test barrel?
Id venture to guess at 11.5 or 12.5 the drop off is going to be drastically more for the 6mm heavies. They are getting 2750-2800 with a 24bbl. If it pushes 103gr Eld x at 2400~2500 in a short barrel config i will be ditching my grendel.
 
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
 
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