6.8 SPC II in an AR 15 vs .308 in an AR 10

[O4L]

Looking in the classifieds today I see one of each, near me, and priced close to the same.

I have zero experience with the AR 10 platform but for ammo costs it seems that the .308 may be the right choice. I'm not planning on reloading either cartridge but I probably wouldn't be shooting hundreds of rounds per year through either one so that may not matter so much.

I was asked just last week if I had any interest in owning an AR 10 and I said no because of the added weight and ammo cost over the AR 15 in .233/5.56 but seeing these ads has me thinking.

I did a bit of research a few years ago for an AR 15 rifle for hunting and decided on the 6.8 but lost access to the hunting area about that time so I didn't start building it.

So if a guy was inclined to add one or the other to his lineup of .223/5.56 AR 15s, for deer, hog, sasquatch, and maybe a little distance shooting, what would you recommend?

Advantages and disadvantages of each one?

Thanks

 

[diggler1833]

I own both. Killed a lot of hogs with both.

If you aren't going to roll your own... .308 all day. Factory ammo costs are similar, but the performance edge goes to the .308 by a lot.. if you do roll your own, the .308 with a 30 cent Hornady Interlock is more effective than the 6.8 with an 80 cent TSX or $1 exotic bullet.

Neither is a ballistic standout regarding target shooting at distance...but the .308 wins in that category too.

The 6.8 will be about 1-1.5 lbs lighter in comparable platforms. 6.8 will also recoil less in similarly setup rifles. My 6.8 is definitely more handy than my .308s.

.308 for magazine and component availability too.

Don't get me wrong, I love my 6.8. It is an extremely underrated cartridge. However, current market trends are probably going to see it pushed more by the wayside in favor of things like the 6 ARC and 6.5 Grendel. The 6.8 fanboys hate this and I'm sure I'll have one find this post and start objecting...but do a Google or Gunbroker search for ammo availability and price, then do the same for firearms in stock.

If I had to pick just one to keep, it would be tough.

 

[KurtM]

Like Diggler1833 said! I've got both as well, on pigs they have very similar performance 16" AR-10, 18" 6.8. velocities are about the same penetration and bullet performance very similar. 6.8 a bit quieter suppressed, and noticably lighter that the 308. 6.8 starting to be a bit**h to find. Long range definitely the 308.

 

[Gunbuffer]

I made that same progression 308> 6.8
Just wish I could use it more!

 

[rockchalk06]

I jumped on the 6.8 wagon several years ago with a 700 LTR and a Custom built 18" AR. I loved the round. It was a jackrabbit/prairie dog killing machine. A prairie dog hiding behind a big clump of mud mixed with cow **** was no match for a 5.56, but send a 100-120 grain SST or the like down range, DRT and a wild clump of poo being vaporized.

Ammo wasn't an issue as I loaded for both it and the .308. Components were about the same either way. I took a few deer with the LTR and it did the job. Nothing like a .308 though. Same with Hogs. .308 with the right bullet, punched way harder and further.

After 300, the 6.8 wasn't a threat anymore. It would kill, but not like it would inside 200ish. .308 I could push much further.

I ended up selling both due to bills and life, but am still considering building another some day. You can build a 6.8 minus the barrel/bolt as cheap as you can any 5.56 and make it a light weight killing machine inside 200ish. You can buy a POF in 308 that is super lightweight, but you will pay for it. Most builds will be on the heavier side. I guess for me, that is the main difference. I haven't priced ammo for either lately, but I would imagine it's about the sameish.

 

[diggler1833]

The 120gr SST is a force multiplier for the 6.8. Up until 2019-2020, you could order it by the case (200 rounds) for about $160 + 30ish dollars for shipping. I didn't bother handloading when I could get that kind of performance for just under a buck a round.

^ of course, you could get the 123gr SST in the Grendel for the same price back then too.

Aside from the SST bullet in the 6.8 though, you get REALLY limited in cost-effective and GOOD hunting bullets in a hurry.

With the .308, I've had some pretty spectacular results using the cheap Federal, Winchester, and Hornady soft points.

 

[wolfkpr]

I spent money.. i bought the new Ruger “ SFAR”, its a 7lbs ish .308 thats about same size/weight as the 5.56 AR rifles.. it was 1150$, but i had 800 in the other, heavier AR-10 i had. So far it runs, is 1.5 moa or so ( only tried 1 load, and the low power variable, so it may do better).. i already have .308, so it means im not adding another caliber...

 

[rockchalk06]

I spent money.. i bought the new Ruger “ SFAR”, its a 7lbs ish .308 thats about same size/weight as the 5.56 AR rifles.. it was 1150$, but i had 800 in the other, heavier AR-10 i had. So far it runs, is 1.5 moa or so ( only tried 1 load, and the low power variable, so it may do better).. i already have .308, so it means im not adding another caliber...

We need a range report on that Ruger brother!

 

[AntTac]

My opinion is stick with 5.56… Shoot 77 grain Sierra Matchking HPBT. Pretty inexpensive if you learn to load them yourself.

 

[ClintC]

I have never had the 6.8. But do own 3 ar10 rifles along with 5.56 rifles. I will say it all depends on how you build the platform. I build mine heavily. My brother builds them light. If it was me and was just going to keep it in 100 yards. 300 blackout.