Why is Remington developing another 6.5mm cartridge for the ACR?

Back in July, when the specification for the original Remington ACR specifications where announced, I said one of the cartridges it would chamber was the 6.5mm Grendel. Remington said “6.5mm”, and in the context I assumed it was the Grendel.

Not long after posting it, I was emailed by a well placed industry insider who told me that he very much doubted Remington would ever produce a gun chambering the Grendel. His reason? The management behind the development of the cartridge left a lot of bad blood in their wake. He suspected that the listing of “6.5mm” was a marketing ploy.

His prediction that Remington would not offer it has come to fruition. Adam Heggenstaller reported (emphasis mine) …

Ongoing development will focus on the 6.8 mm Rem. SPC, 7.62×39 mm, a yet-to-be-disclosed 6.5 mm round and, get this, the .30 Rem. AR.

Will we ever see this cartridge? I don’t know. At least we know why Remington are not just saying “Grendel”.

UPDATE: My original source just emailed me to suggest that the .30 Remington AR necked down would make a lot of sense! He has a good point. (This is just speculation – not inside knowledge).

7.62x51mm NATO, 6.5mm Grendel and 5.56x45mm NATO

Steve Johnson

Founder and Dictator-In-Chief of TFB. A passionate gun owner, a shooting enthusiast and totally tacti-uncool. Favorite first date location: any gun range. Steve can be contacted here.


  • Jerry Kaufman

    What? No .450 bushmaster? the .30AR is the same case just necked down.

  • Pathfinder

    Hmmmm. I thought the 6.8 Rem SPC was a necked down .30 Remington?

    • Pathfinder, .30 Remington is different from the .30 Remington Automatic Rifle (aka. .30 RAR).

  • Clint

    What “bad blood”? Did someone step on some toes or were ideas “borrowed”? Can you give us some details? It sounds like Remington was involved with Grendel development, that’s a new one for me.

  • A proprietary 6.5 makes as much sense as the 30AR–very little sense.

  • Matt Groom

    The reason is probably because they so thoroughly F’d up the SAAMI specifications for the 6.8 SPC. I won’t elaborate, but nearly everybody who knows what SAAMI is knows that the rifling and chamber specifications for the 6.8SPC as submitted by Remington are practically worthless in a Semi-automatic rifle. Rate of Twist, Throat Leade, headspace specifications, all screwed up. Remington ruined that cartridge so badly that they have now distanced themselves from it to the point that none of their new rifles are chambered in this round save the ACR, which they didn’t even develop.

    If you’re buying a 6.8 SPC, get either a SPEC II or a DMR chamber and the slowest rate of twist you can find.

    That said, a 6.5 SPC might be just the ticket to correct the mistakes they made with this chambering that even they must be aware of by now.

    If they base it on the original .284 Winchester case (like the .450 Bushmaster and the .30 RAR) then it will simply be a miniature 6.5-284, which might become popular, but I can’t see how that’s a good idea.

  • kvalseth

    Well, might not be all bad. The 6.5 grendel has the most ridiculous case dimensions. I heard something about that making any sort of belt fed grendel difficult.

  • SpudGun

    Oh boy! Yet another new rifle cartridge, there just aren’t enough of these.

  • Noah

    Well, I was really looking forward to an ACR in 6.5mm Grendel. It seems as though there are a lot of manufacturers who want to make guns chambered in this round, but who are unwilling or unable to go throught the liscencing and IP procedures that the original designer has in place.

    Hey, no biggie, the ACR’s supposed to be able to take modified AR barrels anyway. Just combine a 6.5mm Grendel barrel with a 7.62×39 bolt, and there you go.

  • I think any major company would be wary about adopting another company’s design after Winchester’s fiasco with the WSM and WSSM rounds which they designed based on the Jamison patents and then went under after Jamison sued. AFAIK he still gets a percentage on every WSM rifle and cartridge made and will continue to, as long as these continue to be manufactured. However, without any possible large scale requirement for a new service rifle round, I am not sure if this new design would be more than an engineering exercise. There are several very interesting rounds that have been designed for the M 16 / M 4 platform but how many are being used in any serious quantity by a major army?

  • rm

    The grendel 6.5×39 is a great round but it seems folks don’t want to deal with the guy that “invented” it.
    It is a shame.
    Maybe the 6.5mpc will the 6.5 that survives.
    It would be nice to get the whole story on why so many great arms are not available in 6.5×39.
    No xcr, no pof..now no acr…



    Can the 6.5mpc or the “new” rem round match that?

  • Lance

    Looks like a good weapon.

  • Martin

    I just don’t understand the whole 6.5 series of development. Essentially, with the advent of body armor, and it’s increasing use, .223 doesn’t cut it. Basically we’re talking about an arms race between bullets and body armor. Why fool around with 6.5/6.8 (whatever), and just go back to a .30 bullet (with known ballistics), with an improved case and propellants.

    Being an early adopter of anything, be it ammunition, weapon systems, or software, is a quick way to waste resources on a dead end. That’s why nobody is really jumping on board with all these new rounds. Changing all your tooling is too expensive a gamble. Even buying a new rifle is a risky proposition because if you can’t get ammo for it, it’s a club.

  • Whatever

    It is a real shame that the US military didn’t adopt the 280 British cartridge way back when as it seems ever since then, people have been trying to reinvent something very similar.

  • rm

    Martin if you look at the energy chart on my last post you may be able to understand the benefits of the 6.5.
    Penetration can be handled with ap/steel core bullets regardless of caliber.
    The cost is not a big deal for the gov now is it? 😉
    It would probably not cost much if you consider the 6.5 could replace both the 5.56 and the 7.62 for most applications.

  • Tom

    I think 6.8, 6.5, 5.56 rifles are kind of silly.

    I’m not concerned with recoil because none of my rifles are fully automatic, and I like to take time to aim, even with semi-automatics, I think I’ll keep shooing 7.62x51mm for now so I can be sure whatever needs to be dead, ends up dead.

    People are always like “Oh goodness look at the 6.5’s energy retention at 1000 yards! it’s as good as the thirty!”

    Yeah, except I’m never going shoot anything that I need to kill at 1000′ more like 400 tops. 200 yards is even long.

    Not to mention the cost and availability of high quality 7.62x51mm.

    Sure 6-7mm rounds let you carry more ammunition and have a quick follow up shot. However I don’t have to carry more than 50 ever, and it’s not like I can’t do that .338 Magnum let alone 7.62x51mm. I don’t need 100 rounds, not even for defense against humans, not even in crazy SHTF scenarios.

    Maybe we should all be cambering in 5.8x42mm in case the Chinese invade? Rrriiiggghhttt.

  • rm

    Tom you are welcome to your opinion but it is strange to see you pointing out the advantages of the 6xx and dismissing them as capabilities you are not interested in! You left out the better resistance to wind drift and the slightly flatter trajectory..any others?
    Lots of folks are interested in rounds that have all those advantages. 😉
    The 6.5xx are too good to be useful? 😉

  • Vitor

    Actually the 6.5mm is a great sweet spot, where it bullet doesnt need to be very heavy to have a great BC, nor extremely fast to reach far away (less recoil and barrel wear). The 7.62mm is far from being a sweet spot, a 120grain 6.5 has better BC than a 175grain 7.62mm.

    And Tom, soldiers are concerned about recoil and how much ammunition they can carry and how often they need to change the barrel.

  • Martin


    I’m still with TOM on this one. Modern combat is a <500yd exercise, and all of the 6mm family's improvements at ranges that are not relevant. Just looking at the case size, I don't see how you could carry more. It may have better penetration numbers, for now, but don't think that won't take long correct.

    It might make a good round for a special purpose weapon, but I doubt any of these rounds will hit the mainstream.

  • Dave

    Good for Remington! The intellectual property and licensing requirements of the 6.5 Gr****l are ridiculous. I can’t imagine Remington bending over for Bill Alexander. More folks need to begin ignoring him immediately.

  • Brad

    Makes me wonder how much hair-pulling and squabbling would have been prevented if the original M-1 rifle had just been chambered for the contemporary .250 Savage cartridge. How many ‘ideal’ cartridge concepts have never been attempted if the .250 Savage had gained a foothold as the dominant American rifle cartridge of WWII?

    An M-1 designed for the .250 Savage might have been lighter than the M-1903 rifle, and eliminated the perceived need for the M-1 carbine and the .30 Carbine cartridge.

    I could see a .250 Savage chambered FAL becoming the post-WWII NATO standard weapon which could actually have been controllable firing full-auto. That could have short-circuited the .223 cartridge and the AR-15.

  • latdarkearth@gmail.com

    Nobody’s mentioned that the Grendel case doesn’t properly doublestack in any derivative of the standard AR magazine? The grendel tries to do too much with too little. Too much case/powder volume for too little magwell area. They’re neat for range guns and some kinds of competition, but a combat gun with those or any better ballistics is going to need a different magwell design.

  • rm

    The main problem is what Dave said.
    The mag issue is not a real one..
    ..as seen here..


    Alexander Arms also offers a 26-round stainless spring steel magazine, complete with an anti-tilt follower, a chrome silicon spring, and a black teflon coating.

    Twenty six rounds that perform well enough to threaten 308 fans seems good to me!

  • atek3

    Sorry, but necking down the 6.8 SPC or 30RAR to 6.5mm doesn’t make much sense.

    The former, because the longer case dimension of the SPC vs. the Grendel (43 vs. 39mm) means that useful weight 6.5 bullets (105-123 gr) are too long to fit in AR length magazines.

    The latter, because the 30AR case is so fat it single stacks in AR magazines, so 15 rounds would be a “big” magazine.

    6.5-30RAR COULD be interesting in an NRA OTC Space Gun, but if you go that route, why not go for the already developed and commercially available 6mm AR Turbo.

    Just my two cents.

  • I look forward to seeing what they come up with. Hopefully they will release it to the civilians in the AR market.

  • Pingback: Confederate Yankee()

  • Will be a shame if Remington does (yet another) proprietary cartridge for it’s 6.5mm offering.

    Many, many advantages to the Grendel:

    – Excellent ballistics in reasonable bullet weights for the AR platform. 6.8 can argue muzzle velocity, but the grendel is close there, and wins once you get downrange.
    – Sub-moa accuracy is easy in the AR platform. Case design closely matched to the optimum bullet weight/design/pressure for the AR platform.
    – Mags widely available (C-product, I have about a dozen of them)
    – Already loaded by Wolf, black hills, and now Hornady
    – Reloaders can use commonly available 7.62×39 brass
    – could use common bolt with 7.62×39 if co-designed

    Seems like the soviet’s had no problem with belt-fed MG’s using the case angles on the parent 7.62×39 case…

    Licensing is reportedly reasonable, several mfg’s have done it, and based on the difference between their Grendel & 6.8 offerings can’t be much. IE: the license is not adding much to the cost of the rifle/ammo/mags. With Remington they’d have enough buying power it should be no-issue.

    I agonized very hard over 6.8spc, Grendel, and some of the .30 variants. A year later I’m a hard-core Grendel fan, and am converting my 5.56 carbines over as well. I watch the arguing over the 6.8 chambers, specs, etc and feel like I dodged a bullet (no pun intended).

    Remington, don’t shoot yourself in the foot again!

  • Bill Waites

    Anyone who thinks dealing with Bill Alexander and Alexander Arms to license the Grendel isn’t paying much attention.

    Small shops have done it, big shops have done it, (Les Baer, JT) big companies (notably Wolf, Hornady, Sabre) have done it. The little guys have said the fees aren’t onerous, the big companies obviously don’t think they are either.

    There is a lot of stuff out there that would be libelous if printed, but very little of it is true.

    And now, with Hornady on board, I suspect we’ll see a lot of neat things happening with ammunition, which has been a weak spot in the Grendel world.

  • martin

    Dave: “Good for Remington! The intellectual property and licensing requirements of the 6.5 Gr****l are ridiculous.”

    From that statement Dave, it seems you have a copy of the IP & licensing. Many people have wanted to see that for years.

    Time to ‘put up’

  • Destroyer

    For those that think the 6.5 Grendel is silly, try lugging around your precious 308 in the mountains of afghanistan…nuff said (the 6.5 Grendel has better ballistic properties anyways)

    I think remington is being foolish by blowing off existing cartridges to invent their own. Don’t reinvent the wheel!

  • twilson

    Seems the Grendel has been upstaged by the the “new”, but compatible, .264 LBC-AR. Maybe this is the round that we’ll see Remington introduce?

  • ByronOdmon

    why not just use the .243 instead of the 6.5 grendel, the .556, the 7.62 all of them! it beats the .556 in range and power, beats the 7.62 in recoil and velocity and range of bullet weight.It has almost as much range as the 7.62. i know it is too big for the ar-15/m4 but would it not be worth using in a lightened ar-10 or some other slightly tweaked ar type platform! i see no end to the possible uses for the .243. it uses the same case as the 7.62 nato so that saves the military from changing everything to make the swap! mainly it comes down to i want an ar with a .243 bullet coming out the end damn it! haha

    • sgtcowboyusmc

      Lewis Machine and Tool (LMT) is coming out with an AR Platform that will have interchangeable barrels for the .243, 260 Rem, .338 Federal, 7mm-08 and the 6.5 Creedmore. I looked on their webpage and didn’t see it (I want a 6.5 Creed) but Every Gun Mag I have got recently has a LMT ad showing it. So keep watching LMT’s website for the release of your .243 AR!

  • Shugarshack

    I have been hooked on 6.5 since Killing my first deer with a 6.5×54. I have a Les Baer chambered for the Grendel and love it. When the 450 bushmaster came out I was hoping some one would neck it down to 6.5, call it a 6.5 30 rar or what ever sounds like an excellent idea to me. I have heard nothing of anyone wildcatting it yet but I’m sure it has been done. The AR platform would be perfect for this round a little more case capacity over the Grendel sounds like a dandy deer round rifle/carbine combination. I don’t understand the the negativity towards new cartridge development if you don’t like it don’t buy it the market will take care of it’s self. The 5.56 NATO isn’t cutting it at extended ranges and sometimes not up close, the 308 is a wonderful round but so is the 3006, it was shortened for a reason. Humping extra rounds should be made as easy as possible and those rounds should be as effective as possible. Just saying?

  • charles222

    I just don’t understand the whole 6.5 series of development. Essentially, with the advent of body armor, and it’s increasing use, .223 doesn’t cut it. Basically we’re talking about an arms race between bullets and body armor. Why fool around with 6.5/6.8 (whatever), and just go back to a .30 bullet (with known ballistics), with an improved case and propellants.


    5.56mm NATO is an excellent armor-penetrator, actually. DOJ won’t rate body armor against it.

  • Lawrence

    The .303 British, or 7.7x56mmR is by far the best round in terms of ballistics and range and trumps all other rounds in terms of accuracy. The only problem is the recoil oh yeah fire in short controlled bursts, enemy insurgent down.