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Whatever happened to 6.8? (Page 1 of 4)
Posted: 3/31/2026 12:25:06 PM EDT
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In the early 2000's the 6.8 SPC was pretty much the "third caliber" for AR's to be chambered in. I recall Ruger even issued a 6.8 model of the Mini-14. Whatever happened to the 6.8 craze? |
| It’s been eclipsed by 6.5 Grendel and now the 6ARC. Thankfully parts ammo and components exist so anyone can go that route should they wish. |
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Great cartridge, but: Bad roll-out (I vs II) Somewhat Limited projectiles (90gr-120gr .277) Needed unique bolt Needed unique mags Potential feeding issues when trying to use all AR-15 parts Designed to be a true 5.56 replacement, but it required a near total rebuild (Six8) to truly do it right. |
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I have 2 6.8's and submitting a lower to SBR it. I've had a 12.5" barrel sitting NIW for years wanting to do an SBR. Finally going to get around to it. I have a shit load of XM68GD from when PSA was blowing it out at $8 per 20rd box. And a hell of a lot of reloading components for that cartridge to keep me going for a really long time. |
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| Just bought a lifetime supply of 90-gr Gold Dots for mine. Finally ran out of the 110-gr Speer Pro-Hunters...those were awesome on whitetails. |
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Originally Posted By ALASKANFIRE: It’s been eclipsed by 6.5 Grendel and now the 6ARC. Thankfully parts ammo and components exist so anyone can go that route should they wish. This. It'll be curious if to see if 6ARC does to 6.5 Grendel, what Grendel did to 6.8. I personally don't think so, but while the 6ARC is more popular as it's a better target round, the 6.5 Grendel has the better balance of being good at everything. So we'll see. But yea, 6.8 wasn't a bad round, it just kind of went away. They're still out there. |
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Mine is staying put. I grab it for a few deer hunts. I actually didn’t decide to assemble one until the Valkyrie came out as it gave a quick bump for mags and parts. Bought the barrel fro he who shall not be named with a bolt, a superior adjustible gas block, a closout from a name brand free float forend of which the maker is escaping me at the moment, a couple 5 and ten round mags for hunting and range use. I bought only S&B ammo for the brass. That ammo shot very well for practice. I load with AA2200 and Barnes 95ttsx copper bullets. It’s been an easy project! The most I had to do was fiddle with the gas between the S&B and the reloads. I kind of wish the gas was non tool adjustible like on a FAL. |
The only hyphenated names I like are cartridge names......30-06, 30-40, 38-55 etc.
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Originally Posted By panthermark: Designed to be a true 5.56 replacement, but it required a near total rebuild (Six8) to truly do it right. Someone local is selling a Six8 PSD and a pile of mags and ammo I really don’t need to get into another caliber…but they are cool  I stumbled onto this interesting history thread while I was reading up on 6.8 https://ar15.com/forums/AR-15/6-8-spc-Development-w-5th-SFG-and-USSOCOM-MK12-Variant-/118-785214/ |
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The 6.8SPC is still alive and well. Still the best feeding caliber with a bolt face bigger then .373 Strongest bolt in any caliber with a bolt face bigger than .373 You do not hear about bolt problems or mag problems in the 6.8SPC. Out to 450 yards there isn't a better deer and hog cartridge in an AR15. It didnt have the Hornady push, or the 6.5 craze Hornady created with their marketing. It is reliable, easy to reload, still a wide variety of factory ammo, with new ammo coming out. The list of barrel makers is still long. It is the only larger than .373 bolt face alternate caliber in an AR15 I would trust my life to. |
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My son and I have been killing deer with ours for 15+ years. It just does the job. I loaded up on the $8/box XM68GD years ago and have about 3 lifetimes stocked up. Also loaded up on the 90 grain Gold Dots when they were cheap. What we have hunted with for years have been the 110 grain AccuBonds. I hate that Nosler discontinued them. Ours aren’t going anywhere. Here’s mine that I hunt with. 18” ARP barrel. Attached File |
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Big fan of the 6.8 as well. Absolutely zero feeding issues since acquiring the 6.8 when it came out. I think for the cartridge's design and purpose the bullet weight selection is just fine. I'm still killing deer, hogs, and coyotes with mine. Probably would be the last to go if I had to downsize my collection. I currently have two 18" rifles and they shoot very well, one WOA barrel and one Bison Armory Fulcrum barrel. |
| 300 Blackout happened. It offered enough of the hunting application potential with more parts compatibility and cool factor to eclipse the 6.8 as the favored alternative cartridge. If the 6.8 had better subs and gotten more favor in MIL use, it would have stayed ahead. |
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Interesting. Several post have mentioned 300 (blk) impacting 6.8spc. I've never really thought of the two as competition with each other. To me, 300blk is an MP5SD replacement that can also be a Mk18 alternative. 300blk won't replace 9mm/45ACP/5.56, but it can combine specific capabilities from that cartridges and combine them into one platform that utilizes common 5.56 parts and common .308 projectiles. 6.8spc was specifically designed to replace NATO 5.56 in the M4. Those seem like separate categories with limited (short barrel) crossover....maybe that is where the comparison is coming from? I assume it is a combination of factors (luck, timing, other cartridges) that left 6.8spc without a chair when the music stopped? 6.5G had the benefit of cheap steel case ammo for a bit (before covid), and has longer (if more fragile) legs. 5.56 had a half century of development, usage, and logistics (cheap cost) behind it. 300blk had 5.56 parts, and focused on the sub 10" barrels with both supers and subs. 7.62x39 (at the time) was still a thing and had dirt cheap ammo. 7.62x51/.308/6.5CM often gets left of the conversation, but still exists. Plus every legacy bolt action "deer" gun. 6.8spc seems (to me) to be the best all-around GP performance if you are looking specifically at beating out 5.56/M4 performance out of an AR-ish platform. It is really, really good out to 300, 400, even 500 yards (depending on barrel length and projectile), and that range is really what a lot of people would utilize. But if we were to take all of those popular calibers and compare them out of like-sized (say 14.x) barrels, where does 6.8spc win? Especially when you factor in cost? I think a lot of cartridge comparisons often focus one one or two specific traits from one or two other cartridges that they are trying to outshine, and not look at the entire field. But it does not help when the roll-out gets fucked up. |
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After 6.5 Grendel's kinks got worked out (about 15 years ago) and when $.25 per round Grendel ammo was available (up until 5 years ago), there was no compelling reason to build a 6.8 SPC AR. People all but stopped newly adopting the round. By the time ammo cost became the same as Grendel again, 6.8 had lost too much steam. Beyond that, both Grendel and 6 ARC perform significantly better at medium and long ranges than 6.8 and are easier to get outstanding accuracy from. Whatever advantages 6.8 might have over those rounds for short range hunting are minimal, while its medium and long range target disadvantages are significant. Lots of people like 6.8 for a lot of good reasons, but pretty much nobody is newly adopting it. That's been the case for at least 10 years. It would be interesting for the 6.8 users in this thread to post the year they first got a 6.8 AR. |
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The 6.8 is alive and well. Hornady just released a new 110 grain fmj in their frontier line for it. It’s not burning up the forums with threads about it like the 6 arc is. My 6.8 is my go to for deer and antelope hunting. There are several different offerings in spcii spec ammo available these days that sell out regularly. Blackstone arms seems to sell out of 6.8 barrels and components. It’s a great caliber for what it’s designed for. Every time one of these “what happened to the 6.8” threads gets started it goes for at least couple pages with guys singing it’s praises. OP should build a 6.8 and try it out. |
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There is nothing wrong with the 6.8, there was or is a forum dedicated to the round. I can't hunt anything but pigs with it in Ohio, but it was nice to have. The barrel was hard to get when ARP was around, at least it felt that way. His bolts were awesome too. Que Sera, Sera I have one in 12.5 for sale because I'm getting old. I have plenty of guns and some, for me, with greater use |
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Just made this one last fall. 14.5" barrel, S/A adjustable piston gas block, registered lower. AEM-3 or AEM-4. Attached File I am also working on a 9" piston, AEM 3 suppressed, and a Ruger American Ranch which will also be made AEM-3 or 4 compatible. |
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For me: -Bonded bullets in 5.56 -Realization that the dia and weight of an all copper bullet doesn’t need to be bigger than 5.56 -Tipped match bullets that frag more reliably than OTM in smaller calibers like 5.56 Remember that the 6.8 was a product of the time it was developed. OTM was the only military option better than FMJ. So the caliber testing was all about OTM upset and fragmentation, which favored the larger caliber over better BC. The reality for the market: -Sold as NATO/US 5.56 replacement, didn’t happen -Not the new hotness I like the case better than G/ARC, but marketing is what it is… |
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Have a couple uppers, used it for years on hogs and deer. Recently built a short 308 for that purpose but the 6.8 still makes it out when i need lightweight. Attached File |
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have a pistol, thinking of building up the 18" YHM barrel I have into another rifle. Hornady putting out a Frontier product is a good sign. the only domestic loads I can find now are the three expensive Hornady products. would be good to see inexpensive domestic ammo. range ammo has been PPU and S&B since I finished mine 2 years ago. |
The deuce you say.
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Originally Posted By racer765: have a pistol, thinking of building up the 18" YHM barrel I have into another rifle. Hornady putting out a Frontier product is a good sign. the only domestic loads I can find now are the three expensive Hornady products. would be good to see inexpensive domestic ammo. range ammo has been PPU and S&B since I finished mine 2 years ago. I bought a bunch of brass and powder for reloads but I don't know when I will have the time when it warms up enough in my reloading area. |
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Originally Posted By cttb: It would be interesting for the 6.8 users in this thread to post the year they first got a 6.8 AR. 
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Originally Posted By fulautotank: I started my venture into 6.8 around 2007ish. My favorite is the SSA 85 gr barnes TL. Still shooting my stash I still have a little SSA 110 and 115gr around. My original was a Ruger 556 in 6.8 which was not the spec II chamber so I never purchased any of the hotter rounds they made. Now I wish I had for my new 6.8-II rifles. Sometimes you can buy 90gr rounds from Cavity Back Bullets, that makes them. They make a bunch of different offerings but they are for the hotter spec-II chamber only. |
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Originally Posted By BM1455: I still have a little SSA 110 and 115gr around. My original was a Ruger 556 in 6.8 which was not the spec II chamber so I never purchased any of the hotter rounds they made. Now I wish I had for my new 6.8-II rifles. Sometimes you can buy 90gr rounds from Cavity Back Bullets, that makes them. They make a bunch of different offerings but they are for the hotter spec-II chamber only.  Since it was threaded 1/2x28 it was a 5.56 mount and those 6.8 projectiles had to squeeze through that little hole. Oops.
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Originally Posted By fulautotank: My first 6.8 barrel was threaded 1/2x28. I threw an AAC mount on it so that I could use my 308 suppressor. Luckily when I first shot it I didn't put the suppressor on it. I shot a few rounds to sight it in and I couldn't see an impacts on the target after each round. There was absolutely no recoil. Since it was threaded 1/2x28 it was a 5.56 mount and those 6.8 projectiles had to squeeze through that little hole. Oops.Yikes. I have two 6.8 AE cans. I have another 5.56 one so I need to make sure I don't put that 5.56 on there. |
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Originally Posted By cmeyer001: Have an ACR in 6.8 and a 6.8 barrel for my MRP. Great pig cartridge. I would think so and I still fight building one for hunting alone. I waited for the cartridge to gain a little more steam and it fizzled out. I think it’s perfect for medium sized game and military/LE work but it’s not going anywhere now. It’s a shame though, it checks a lot of boxes. |
If a 147 grn 9mm at 1000 FPS is the hammer of Thor then a 165 grn. 40 at 1200 fps must a lightening bolt from Zeus!
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Originally Posted By Colt653: 5.56 NATO https://www.ar15.com/media/mediaFiles/2275/IMG_0092_jpeg-3740148.JPG 6.8SPC https://www.ar15.com/media/mediaFiles/2275/IMG_0093_webp-3740149.JPG 
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Originally Posted By fulautotank: Funny but true Originally Posted By fulautotank: Originally Posted By Colt653: 5.56 NATO https://www.ar15.com/media/mediaFiles/2275/IMG_0092_jpeg-3740148.JPG 6.8SPC https://www.ar15.com/media/mediaFiles/2275/IMG_0093_webp-3740149.JPG That is a tasty analogy |
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Originally Posted By FB41: I'll get rid of my .223 AR's before my 6.8 goes. Attached File |
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Whatever happened to 6.8? (Page 1 of 4)
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