Anyone own an AR chambered for 6.8 spc? opinions...

[spainy79]

Thinking about a fourth build and was leaning towards a 204 upper but the 6.8 spc seems to be a better fit for number 4. Wondering what owners or anyone with experience with the round thinks about it? Good/bad? What you say? My first thought for this is to use for yotes. I'm not looking to start this build anytime soon so that's why I'm asking now rather than to wait and dig up info when I do decide to build.

 

[aclark]

I know this has been discussed at length a few times here, and melensdad would be the one to really ask, but depending on what you want it for, take a look at the 6.5 Grendel. Its gaining in popularity, but doesn't have the backing yet that the 6.8 does; however, ballistically its a superior round for distances past 300yds. A lot of popularity growing in some shorter barrel setups as well, anything from 10.5 to 16", and on up to 20-24" barrels.

 

[spainy79]

I went to bed right after starting this thread and the first thing I thought of after laying down was I should've tried to search the subject on here first. Oh well. I have been looking at the 6.5 and also the 243 wssm. For some reason the 6.8 appealed to me more.

 

[melensdad]

I went to bed right after starting this thread and the first thing I thought of after laying down was I should've tried to search the subject on here first. Oh well. I have been looking at the 6.5 and also the 243 wssm. For some reason the 6.8 appealed to me more.[/b]

Why, do you like slower, lower Ballistic Coefficient bullets that lose their energy faster and have more arc?

Honestly the 6.8SPC II spec is the better choice in SBR and carbine length rifles for close quarters combat fighting. The round burns more efficiently in a short barrel gun than does the 6.5 Grendel or the 243 Win. The 6.8 SPC II is also better if you run a suppressor on your gun because the 6.5 Grendel and the 243 Win both crack supersonic speeds and don't seem to run semi-autos reliably when they are downloaded to sub-sonic speeds. As the 243 Win won't run in an AR15 platform gun I'll omit it from my comments from this point out.

But any barrel length beyond 16" and there is a clear advantage to the 6.5 Grendel. Even at 16" the Grendel is as good as the 6.8 SPC II.

You said you wanted to use the gun for coyotes and that means you will logically be looking at 18?, 20, 22 or even 24 inch barrels. With any of those barrels the 6.5 Grendel will be clearly superior at every range.

Here are the ballistics for the current loadings from Silver State Armory, the items marked TACTICAL are the SPC II spec loadings:

Here is a comparison between several popular loads:

Compare the energy levels. The 6.5 Grendel holds its energy twice as far as the 6.8 SPC.

 

[sig1473]

6.5 Grendel is tough to beat. Too bad factory-loaded ammo is in short supply

 

[spainy79]

What got the ball rolling on this is a buddy mentioned getting rid of his 270 bolt gun in favor of an AR. I'll admit I didn't research it very hard; seen the 6.8 and came straight here to ask for opinions. I didn't really compare it against the 6.5 till Aclark talked it up. I'll chalk it up to poor research on my part. I've already emailed my buddy to inform him about the 6.5 and hopefully get him on the right track. Thanks for the helpful info. I'm even debating getting rid of my 16" 5.56 upper for this. Still can't decide if I want to build up another lower. I probably will.

 

[melensdad]

What got the ball rolling on this is a buddy mentioned getting rid of his 270 bolt gun in favor of an AR. I'll admit I didn't research it very hard; seen the 6.8 and came straight here to ask for opinions. I didn't really compare it against the 6.5 till Aclark talked it up. I'll chalk it up to poor research on my part. I've already emailed my buddy to inform him about the 6.5 and hopefully get him on the right track. Thanks for the helpful info. I'm even debating getting rid of my 16" 5.56 upper for this. Still can't decide if I want to build up another lower. I probably will.

Aaron is building an awesome full custom long range 6.5 Grendel now. I currently own 2 6.5 Grendels, and had a third one at one point, all built on AR15 platforms. I purchased a CZ 527 bolt action rifle that I hope to rechamber to 6.5 Grendel at some point. The round is not perfect, but it maximizes the AR15 platform's range with minimal recoil.

As for ammo, I buy it mail order and usually in bulk. I've been able to buy some of the Wolf reloadable brass 123 grain soft points for 52 to 65 cents a round (delivered price) and the Wolf reloadable brass 120 grain MTP rounds for about 75-cents a pop. Despite Wolf's spotty reputation I've been able to shoot better than 1/2 MOA at 200 yards and I loaned the gun to a friend who shot even tighter groups than I can get. Basically we are talking about accuracy that will hit a coyote in the ear at 300 yards. Premium 6.5 Grendel seems to cost between $1 and $1.25 a pop, but honestly I almost never shoot it because I have such good luck with the Wolf stuff, but I know guys who can't get good groups with the Wolf ammo, so I suggest you try several different types of ammo and settle on the one that shoots the best for you.

6.8 SPC II rounds seem to cost about $1 per shot for the cheapest stuff I can find. I did own a 6.8 and was so disappointed with it that I sold it pretty quickly, I'll admit it was an early generation version, but even the newest generation can't really match the 6.5 unless you really over-pressure the cartridges and use them in the newest chambers with the slower twist rate barrels.

 

[aclark]

Bob is the one that got me on it when I was looking for something other than 5.56 and didn't want a .308 bolt gun. While I don't have the in depth knowledge of the round that he does, I am indeed working on a nice little build, and hope to have it complete by the end of the year. I still need to research the reloading and ammo aspect of it, but that will come in time after I have everything I need. While 6.8 is more readily avail right now, 6.5 isn't that hard to find online, albeit slightly expensive right now. If you can roll your own the "match grade" will run you about .40 to .50 a round.

 

[melensdad]

Oh, one thing that I'd like to point out about the ballistics table that I posted.

That table is based on the ORIGINAL data from the 6.8 SPC and shows it with the original Remington 115grain OTP load. That is the load that was designed for the military. That load showed a velocity of 2700 feet per second. It does not exist. There is no commercially available load in the 6.8 SPC or even the newer 6.8 SPC II/Tactical that will push a 115 grain bullet at that speed.

So given that, the ballistics chart is showing OVERLY OPTIMISTIC numbers for velocity and energy at every range for the 6.8 SPC loads. In fact, you need to downgrade the velocity by 200 feet per second, which correspondingly downgrades the energy, and consequently increases the affects of bullet drop as well.

When its all said and done, the 6.8 SPC is LESS COMPETITIVE than those charts above would lead you to believe.

Now the 6.8 SPC fan boys my jump in here and 'correct' the data, but I'd caution you to ask them how much those specialize bullets they are throwing down range. To get Grendel levels of performance, I've seen some of the 6.8 guys use lathe turned bullets at shockingly expensive costs, in special barrels, at higher than factory pressures. Which seems like it would wear out a gun, lead to premature bolt breakages, flattened primers, etc.

I really can't say anything bad about the 6.8 SPC. Its a good round in and of itself. Just like the 100 year old 30-30 Win. In fact the ballistics of the two rounds are pretty similar. The old 30-30 is clearly the deer killing champion in this nation so its tough to criticize. And if you are looking for a modern day round with 30-30 ballistics then the 6.8 SPC would be a great choice. If you want to run a heavier bullet in an NFA gun like a SBR or a suppressed gun then the 6.8 SPC is a better choice than a 5.56. But if you are looking for a round that maximizes the performance of the AR15 platform in any barrel length that is 16" or greater, it seems to me the 6.5 Grendel is clearly the superior round for that task.

 

[melensdad]

On last chart for you:

Many sportsmen agree that 1000 ft lbs of energy is the 'humane' minimum for killing Deer size game quickly, the 6.5 Grendel carries that to about 400 yards, the 6.8 SPC only to 200 yards. The military standard to disable a man is 500 ft lbs of energy. The 6.8 SPC runs out to 500 yards, which is just about the same as the current 5.56 military loading. The Grendel runs that out to over 850 yards and the bullets stay supersonic out past 1000 yards.

Not that most of us shoot out at those ranges, but its nice to have it on tap if you get a chance to take your gun out to a longer range shooting area.

As for recoil, my daughter has been comfortably shooting my Grendel rifles since she was 12 or 13 years old.

 

[melensdad]

6.5 Grendel is tough to beat. Too bad factory-loaded ammo is in short supply

Not sure where you shop but its in stock and available to order from a couple places that I just checked. Starting at about 75-cents a round, going up to $1.50 for the super premium stuff.

Google is your friend when shopping for ammo.

 

[aclark]

Oh, one thing that I'd like to point out about the ballistics table that I posted.

That table is based on the ORIGINAL data from the 6.8 SPC and shows it with the original Remington 115grain OTP load. That is the load that was designed for the military. That load showed a velocity of 2700 feet per second. It does not exist. There is no commercially available load in the 6.8 SPC or even the newer 6.8 SPC II/Tactical that will push a 115 grain bullet at that speed.

So given that, the ballistics chart is showing OVERLY OPTIMISTIC numbers for velocity and energy at every range for the 6.8 SPC loads. In fact, you need to downgrade the velocity by 200 feet per second, which correspondingly downgrades the energy, and consequently increases the affects of bullet drop as well.

When its all said and done, the 6.8 SPC is LESS COMPETITIVE than those charts above would lead you to believe.

Now the 6.8 SPC fan boys my jump in here and 'correct' the data, but I'd caution you to ask them how much those specialize bullets they are throwing down range. To get Grendel levels of performance, I've seen some of the 6.8 guys use lathe turned bullets at shockingly expensive costs, in special barrels, at higher than factory pressures. Which seems like it would wear out a gun, lead to premature bolt breakages, flattened primers, etc.

I really can't say anything bad about the 6.8 SPC. Its a good round in and of itself. Just like the 100 year old 30-30 Win. In fact the ballistics of the two rounds are pretty similar. The old 30-30 is clearly the deer killing champion in this nation so its tough to criticize. And if you are looking for a modern day round with 30-30 ballistics then the 6.8 SPC would be a great choice. If you want to run a heavier bullet in an NFA gun like a SBR or a suppressed gun then the 6.8 SPC is a better choice than a 5.56. But if you are looking for a round that maximizes the performance of the AR15 platform in any barrel length that is 16" or greater, it seems to me the 6.5 Grendel is clearly the superior round for that task.

I would also add that if you wanted a heavier bullet in an SBR then why not look to the 300BLK which was made for suppressed SBRs. You're velocities wont be as high as the 6.8, but you can still get out to 400-500yds if you wanted. However, it is way superior in a shorter barrel, and made to be suppressed. Basically the 6.8 is caught between the two, and doesn't out perform either at any particular task.

 

[blownz28]

I like my ar pistol witn a 10.5 inch 6.8 ar performance barrel. Seems to be doing pretty good. I run the hornady stuff through it. As soon as my stamp gets here, it'll be wearing a Ti suppressor.

I also have a 24 inch saturn 6.5 grendel barrel, getting components to finish up.

I think both calibers have their place. The 6.8 is a bit finicky with mags, feed angle and such. I hope the 6.5 isn't. Dunno, we'll find out.