[XDm_Shooter]

Hey again guys, just got another quick question. I picked up my Spikes Tactical Lower today and am reconsidering the 6.8 SPC. I don't know too much about the 6.8. While I am doing some research on it I am curious what you all think of the round.

Will the 6.8 SPC and 5.56 rounds use the same magazines? Looking at my reloading manuals and they show the OAL to be the same (2.260") and the COAL on the 5.56 actually a little longer. Case for 5.56 shows 1.760" while 6.8 SPC shows 1.6864" and the 6.8 slightly "fatter".

Thanks for your help!

 

[John A.]

I own both 5.56 and 6.8.

They both will work from the same lower if that's what you're asking.

But the 6.8 bullets really need their own magazine.

However, you can fit and fire between 5-7 rounds of 6.8 spc from a regular 5.56 magazine, but more than that causes most aluminum and polymer body mags to swell and not fit into the receiver magwell.

That's why all dedicated 6.8 mags are made from stainless steel. (Barrett, PRI, Cproducts, D&H [soon] and others.)

Never tried firing 5.56 from a 6.8 mag though. Maybe next time I go out just for grins and giggles.

Just FWIW, 6.8 uses .30 caliber brass and necked down for .270 bullets.

They hit much harder than 5.56, and are faster and have better trajectory and penetration than 7.62x39.

The only downside to the 6.8 is the ammo costs more than 223 and 7.62x39. But I have other guns for plinking.

 

[jn_fsu]

I read this but and have wanted a 6.8 SPC ever since...
6.8 mm SPC Cartridge History & Development. Hornady's Ammunition. The Stag Carbine.

 

[XDm_Shooter]

.....But the 6.8 bullets really need their own magazine.

That answers my question...thanks!

 

[N.E. Tx.XD]

Look at the balistic tables and consider the 6.5 Grendel also. 7.62x51 performance outta your AR15 lower.

 

[Lopper]

6.5 is the way to go

 

[AR-15 Rep]

The military was actually using 6.8mm in Afghanistan back in 2004. Many hunters like the 6.8 and it is less expensive than the 6.5

 

[John A.]

The military was actually using 6.8mm in Afghanistan back in 2004. Many hunters like the 6.8 and it is less expensive than the 6.5

And more available and in a much broader bullet choices too.

 

[Griff]

checkout 68forums.com

 

[XDm_Shooter]

6.5 is the way to go

Aside from having an issue finding anyone local that carries ammo for the 6.8 SPC I would like to go with it I think. Another issue that I am having is finding a complete upper to my liking. I want at least 22" Stainless Steel bull barrel for this build. These are not easy to find from what I have found. Longest ones that I can find are 20"....

 

[Fdxpilot]

Aside from having an issue finding anyone local that carries ammo for the 6.8 SPC I would like to go with it I think. Another issue that I am having is finding a complete upper to my liking. I want at least 22" Stainless Steel bull barrel for this build. These are not easy to find from what I have found. Longest ones that I can find are 20"....

The 6.8SPC doesn't gain much from the very long barrels, like the 6.5 or 5.56. That's why you don't find 22" barrels. The longest barrels you will commonly find, even from specialty shops like AR Performance, are 18". Of the 4 6.8s I have owned, 2 were 16" and 2 were 18". There is only a 50fps or so difference between the two. Just my opinion, but anything over 18" is just unnecessary added bulk and weight.

 

[XDm_Shooter]

The 6.8SPC doesn't gain much from the very long barrels, like the 6.5 or 5.56. That's why you don't find 22" barrels. The longest barrels you will commonly find, even from specialty shops like AR Performance, are 18". Of the 4 6.8s I have owned, 2 were 16" and 2 were 18". There is only a 50fps or so difference between the two. Just my opinion, but anything over 18" is just unnecessary added bulk and weight.

Good information there...thanks! Guess that shows what I know huh? 50fps is not enough to worry about...as long as the accuracy at around the 600 yd mark is still there.

 

[Fdxpilot]

Good information there...thanks! Guess that shows what I know huh? 50fps is not enough to worry about...as long as the accuracy at around the 600 yd mark is still there.

Are you actually going to be shooting at 600yds? At that range, the 6.5Grendel might actually be a little more accurate. The 6.5 bullets generally have a little higher BC and lose velocity a little slower, so there is less drop or windage at long range. However, I don't think either the 6.5 or 6.8 is going to have a whole lot of energy that far out, so if you are actually hunting, you may need something a little bigger. There is a reason the US Army is scrounging up M14s and the British Army is buying LMT 7.62s for the long range shooters in Afganistan. I love my 6.8, but I wouldn't try shooting hogs at much over 200yds. Of course, I'm used to MS and TX for shooting. You have some wide open country in Grand Junction.

Check this link

http://68forums.com/forums/showthread.php?21222-shot-my-ARP-Recon-16-quot-upper-at-565yds

BTW- Just coincidence, but I'm currently looking out a window at the Doubletree on I-70 by the GJT airport. Gotta take that big white and purple jet loaded with letters and packages back to Memphis in a couple hours

 

[XDm_Shooter]

Are you actually going to be shooting at 600yds? At that range, the 6.5Grendel might actually be a little more accurate. The 6.5 bullets generally have a little higher BC and lose velocity a little slower, so there is less drop or windage at long range. However, I don't think either the 6.5 or 6.8 is going to have a whole lot of energy that far out, so if you are actually hunting, you may need something a little bigger. There is a reason the US Army is scrounging up M14s and the British Army is buying LMT 7.62s for the long range shooters in Afganistan. I love my 6.8, but I wouldn't try shooting hogs at much over 200yds. Of course, I'm used to MS and TX for shooting. You have some wide open country in Grand Junction.

Check this link

shot my ARP Recon 16" upper at 565yds

BTW- Just coincidence, but I'm currently looking out a window at the Doubletree on I-70 by the GJT airport. Gotta take that big white and purple jet loaded with letters and packages back to Memphis in a couple hours

LOL...welcome to Grand Junction!! The desert out there around the airport is where a lot of us locals go out and shoot. There is a LOT of country out there that is away from everything so safe for shootin'.

Don't suppose the 6.5 will work on an AR Lower huh? That's another one that seems to not be real popular out here as far as anyone carrying ammo...

 

[Fdxpilot]

LOL...welcome to Grand Junction!! The desert out there around the airport is where a lot of us locals go out and shoot. There is a LOT of country out there that is away from everything so safe for shootin'.

Don't suppose the 6.5 will work on an AR Lower huh? That's another one that seems to not be real popular out here as far as anyone carrying ammo...

The 6.5 will work on a standard AR lower. That is the plus, but also the minus. Given the space restrictions of the AR magwell and upper receiver, it is tuff to fill a cartridge with enough power to really pack a wallop at the ultra long ranges (which I consider anything over about 400 yds.) However, if you are just shooting targets, either 6.5 or 6.8 will get the job done, with the 6.5 getting the nod at really long range.

While I know the Marines shoot out to 500yds with the M16, they are using a man sized target, not making hunting kill-shots. As I mentioned, with an AR, I can be assured of a decent shot out to at least 200yds. After that, my personal accuracy suffers, and the bullet energy drops, to where I can't make a good kill-shot with any certainty. With my .308 Remmy 700, I can still have enough energy to drop a deer or hog even if the shot is off a little. Of course, a lot of that is my own personal limitation, and you may be a lot more accurate at long range.

 

[XDm_Shooter]

Are you actually going to be shooting at 600yds? At that range, the 6.5Grendel might actually be a little more accurate. The 6.5 bullets generally have a little higher BC and lose velocity a little slower, so there is less drop or windage at long range. However, I don't think either the 6.5 or 6.8 is going to have a whole lot of energy that far out, so if you are actually hunting, you may need something a little bigger. There is a reason the US Army is scrounging up M14s and the British Army is buying LMT 7.62s for the long range shooters in Afganistan. I love my 6.8, but I wouldn't try shooting hogs at much over 200yds. Of course, I'm used to MS and TX for shooting. You have some wide open country in Grand Junction.

Check this link

shot my ARP Recon 16" upper at 565yds

BTW- Just coincidence, but I'm currently looking out a window at the Doubletree on I-70 by the GJT airport. Gotta take that big white and purple jet loaded with letters and packages back to Memphis in a couple hours

I don't plan on making a habit of shooting out that far, but would like to know that the option is there should I need/want to. I was wanting to stay with the 5.56, then changed my mind to the .308...then went looking at 6.8...then went back to my original plan of the 5.56. I have been back and fourth on which would be best. I suspect the majority of my shooting to most likely be well within the 400 yard range but would like to know that the option of reaching out is there. Thing is I have a Spikes Tactical lower already that I am building. If memory serves me the .308 will not fit the standard AR lower or am I mistaken here?

I am liking this Stag 6.8 and here is the 5.56 that I was originally looking at and seriously considering....

 

[N.E. Tx.XD]

IMO the 5.56 was made to maime or kill a man or varmits. I wouildn't shoot at anything bigger than a coyote beyond 300 yds with a AR15. If your hunting big game at long ranges, just step up to a AR10 lower, and go from there. There is a reason the military does.

For plinking....a hopped up 10-22 makes the most economical sense.

 

[XDm_Shooter]

IMO the 5.56 was made to maime or kill a man or varmits. I wouildn't shoot at anything bigger than a coyote beyond 300 yds with a AR15. If your hunting big game at long ranges, just step up to a AR10 lower, and go from there. There is a reason the military does.

For plinking....a hopped up 10-22 makes the most economical sense.

Not going to be hunting any big game with it...state requires at least .24 cal anyway...we have some big a** big game here in Colorado...specially Western Colordo. I have my big game gun already 300H&H Mag using a 190gr Hornady BTSP over 58.6gr of IMR 4831. IMO I would not recomend shooting any big game out here with lest than a .27 cal.

This builds only purpose is going to be varmints and targets. I am not too worried about the "economical sense" of shooting...again IMO, if I can't afford to shoot it I can't afford to have it...reloading my own helps a lot as much as I shoot. Like I said before too, I would expect that the great majority of my shooting will be within 400 yds, I would just like to know that if I need/want to extend past that, that the option is there. I would not be shooting anything bigger than a coyote with it more than probably the 400yd mark as you said you would also not do. Longer range is an interest for target shooting more than anything else...

 

[jn_fsu]

This has some interesting information. Maybe it will help...
Modern Firearms - Assault rifle ammunition

 

[Fdxpilot]

I don't plan on making a habit of shooting out that far, but would like to know that the option is there should I need/want to. I was wanting to stay with the 5.56, then changed my mind to the .308...then went looking at 6.8...then went back to my original plan of the 5.56. I have been back and fourth on which would be best. I suspect the majority of my shooting to most likely be well within the 400 yard range but would like to know that the option of reaching out is there. Thing is I have a Spikes Tactical lower already that I am building. If memory serves me the .308 will not fit the standard AR lower or am I mistaken here?

I am liking this Stag 6.8 and here is the 5.56 that I was originally looking at and seriously considering....

I would urge you to pass on the Stag. I had a Stag 5H, which is their 16" carbine 6.8. During the 8 months or so that I had it, I could never get it to feed reliably. This was with every kind of 6.8 ammo and magazine I could get my hands on. While I realize this does not mean every Stag 6.8 is a dog, they have had significant problems with their 6.8 rifles. For one thing, although the original and Spec II specs call for M4 feed ramps for the larger cartridges, Stag until very recently refused to use them. If you have perused the 6.8 forums, you might have seen a poll from this past winter. It showed that 43% of the Stag 6.8 owners (5H and 7H) that responded had had some sort of feed problems. Given the other alternatives in all price ranges, I can't recommend a Stag 6.8 to anyone.

If you want a high quality upper, may I suggest either Bison Armory or AR Performance. I personally have owned 2 AR Performance uppers, and that is what replaced my Stag. Harrison, who runs AR Performance (posts here as "Constructor",) is one of the definitive authorities on the 6.8, and was instrumental in the newer improved specs for the cartridge. He can build you anything from a basic M4 style 16" midlength to a long barreled Stainless target or hunting rifle. Plus he is right down the road in Pueblo West.

If you want to get into the 6.8 on a budget, stay with Palmetto State, but get one of their house-brand 18" stainless uppers. While they are currently out of stock, they have been in and out since the introduction a couple months ago. I recently picked up one of these as a second upper for my Daniels 5.56, so my kid could have a 6.8 when we go hunting hogs.

As to .308s, you remember correctly. AR styled 7.62x51/.308 rifles are built on several different, larger, non-compatible platforms. While some small parts will interchange, like handgrips, the major parts like upper and lower receivers, won't interchange with each other, or the AR15 platform.