Updated Info on 6.8 SPC

[Equalizer_2]

For those interested, about three months back there was a thread started on 68forums.com and then copied over to ar15.com by the author updating information on what has happened to the 6.8 SPC over the last two years or so. This round has come quite a ways from what was originally offered by Remington as it appears they received some bad specs that limited the capabilites of the round's true potential.

Go here and read what the current specs offer for this round,http://www.ar15.com/forums/topic.html?b=3&f=121&t=449200

I have used factory loaded 110 gr VMAX bullets, which are a varmint bullet, to punch holes in 3/16" mild steel plate and the holes were larger than the hole punched by a .308 FMJ in the same piece of metal.

There are a lot of deer and tons of wild hogs that have been taken with this cartridge along with at least one elk and one bear. Others are out to increase the number of bear and elk. With proper bullets this can be done.

If you believe that a .243 is a viable hunting cartridge then the 6.8x43 will fill the same bill. The fastest .243 load with a 90 gr bullet I find in one of my loading manuals is 3243 fps using 47.3 grs of powder and a 24 inch barrel in a universal receiver. The 6.8x43 can push a 90 gr bullet at 2900 fps from a properly speced 16 inch barreled AR-15 and it does this with around 30 grains of powder. A properly speced 20 inch AR should raise this velocity by 100 to 200 fps. A properly speced 20" barrelled 6.8x43 can push a 110 gr bullet to between 2800-2850 using about 30 grains of powder, this equals the best the .243 can do with a 105 gr bullet with 47.5 grains of powder in the same 24 inch barrel and universal receiver at 2839 fps.

Not bad for a lightweight, semiauto rifle.:D

[Redleg]

I've been thinkinng about a 6.8 myself. But I'm not clear here. If this is using the .243 case, the .243 being a necked down .308, why wouldn't you just go to an already existing 7mm-08 instead? That'll give you 2800 fps with 140 gr.

[Fronty Owner]

I've been thinkinng about a 6.8 myself. But I'm not clear here. If this is using the .243 case, the .243 being a necked down .308, why wouldn't you just go to an already existing 7mm-08 instead? That'll give you 2800 fps with 140 gr.

from my understanding, 6.8 is a .223 necked up and loaded differently. I hadn't investigated much tho.

[tightgroup]

From the little investigation that I have done, the 6.8 is based on the obsolete 30 Remington case which has a .422 head. The 5.56 case has a .378 head and the 7.62X51 has a .473 head.

Personally, the results I have seen from a 5.56 that is loaded with a heavy hollowpoint are adequate for me to stick with the caliber.

If I was military, shooting FMJ, then I would want the bigger diameter.

[Fronty Owner]

no, no, no!

you gotta have aleast a .300 win mag for varmints. you wanna shoot anything bigger than a coyote, get a .338 Lapua.

[Redleg]

no, no, no!

you gotta have aleast a .300 win mag for varmints. you wanna shoot anything bigger than a coyote, get a .338 Lapua.

So you can kill them with an aftershock if you miss?:cool:

[Fronty Owner]

So you can kill them with an aftershock if you miss?:cool:

hang out on enough gun forums and that is one theme you will see quite often...

I think alot of people carry WAY too much gun. Ive see too many white tail deer taken with .22LR

Back to the subject, when ammo is more available, I may look at getting a 6.8 upper for my AR.

[Equalizer_2]

I've been thinkinng about a 6.8 myself. But I'm not clear here. If this is using the .243 case, the .243 being a necked down .308, why wouldn't you just go to an already existing 7mm-08 instead? That'll give you 2800 fps with 140 gr.

tightgroup has the dimensions correct. The difference in using the 6.8 is that it fits the same lowers as the 5.56 yet has superior terminal performance. Anything that uses the .308 case must use a lower for an AR-10.

I have not checked but a barrel with the correct specs should be able to hit close to 2500 fps with a 130 gr bullet. The Speer 130 gr HotCore has a BC of .408 which is pretty good so it offers good potential. The 6.8 uses the same diameter bullets as the .270 and as there are only three other cartridges using the .277 diameter bullet we are trying to get the bullet manufactures to design and produce more and better bullets in that caliber with an emphasis to the lighter weights around 110 gr.

[Equalizer_2]

Back to the subject, when ammo is more available, I may look at getting a 6.8 upper for my AR.

There are a number of manufacturers loading 6.8 ammo with the premier loader being Silver State Armory (SSA) or ssarmory.com

No one loads as many different loads and configurations as SSA and I have had no problems getting about 1200 rds and 600 cases from SSA alone. I have some Remington, Hornady, and BVAC also just not as much because as I said, SSA is the premier manufacturer.

Other manufacturers include Remington, Hornady, S&B, and BVAC. I know there are a few others so it is becoming available.

[Redleg]

I have not checked but a barrel with the correct specs should be able to hit close to 2500 fps with a 130 gr bullet. The Speer 130 gr HotCore has a BC of .408 which is pretty good so it offers good potential. The 6.8 uses the same diameter bullets as the .270 and as there are only three other cartridges using the .277 diameter bullet we are trying to get the bullet manufactures to design and produce more and better bullets in that caliber with an emphasis to the lighter weights around 110 gr.

So how does that correspond with the rifling available? Most are offering 1:11 I think? Is that optimum for the lighter bullet? I'm under the impression for combat or hunting, we'd want the heavier bullet available? Are you looking at the light for better accuracy in the barrels offered? Would there be a faster barrel available for the heavys?

[Fronty Owner]

There are a number of manufacturers loading 6.8 ammo with the premier loader being Silver State Armory (SSA) or ssarmory.com

No one loads as many different loads and configurations as SSA and I have had no problems getting about 1200 rds and 600 cases from SSA alone. I have some Remington, Hornady, and BVAC also just not as much because as I said, SSA is the premier manufacturer.

Other manufacturers include Remington, Hornady, S&B, and BVAC. I know there are a few others so it is becoming available.

no, I mean Pre-Dahlibama levels of available...

[Equalizer_2]

So how does that correspond with the rifling available? Most are offering 1:11 I think? Is that optimum for the lighter bullet? I'm under the impression for combat or hunting, we'd want the heavier bullet available? Are you looking at the light for better accuracy in the barrels offered? Would there be a faster barrel available for the heavys?


Rifling rate is also affected by velocity and the velocity range of the 6.8 has all the bullet weights performing very well. There are not a lot of loads published yet on the 130 gr but all indications are it is very accurate in the 1/11 and 1/12 twist rifles. The 85 gr Barnes TSX hits about 3000 fps and the 115 gr OTM Tactical load hits about 2550 fps and the 110 gr Sierra ProHunter hits 2575 in 16" 1/10 twist barrels. Accuracy of course depends on the shooter, barrel, and other factors as you are aware but there are claims of sub-MOA groups for all the loads but of course not by every shooter.

It was found that by using the 1/11 twist rifling that when combined with what is called the SPCII chamber they could get almost 200 fps higher velocities with lower pressures over the 1/10 twist barrel with the original SAAMI chamber. The difference is that the SPCII chamber has a longer leade than the SAAMI and that reduces pressures by about 3000 psi alone. Add the slower rifling twist of the 1/11 and you can add powder and increase the velocity without increasing pressure.

Bill Wilson of Wilson Combat is about to start offering a 6.8 rifle/carbine also. He has joined 68forums.com and has become a convert. He killed 4-6 hogs ranging up to 222# in one week hunting on his ranch with a 6.8 and has become a believer.

Bill has a couple of loads developed for his 1/10 twist rifle that hit 2300 fps out of a 16" barrel I believe he is using. I have seen untested load data using a 18" barrel where one load hits 2608 fps with the 130 gr Speer SP and a couple of other loads that hit right at 2500 fps.

[Equalizer_2]

no, I mean Pre-Dahlibama levels of available...


At the last gun show I attended I saw factory 6.8 ammo on two of the three table holders that only deal in ammo. They had several boxes and at least 2 different loadings each. And each table had a different brand of ammo, one was SSA and the other was BVAC. I believe that 6.8 availablity will increase just like other calibers. As a matter of fact last week Cabelas was running a sale on 90 gr TNT loads from SSA that was actually a little better priced than SSA was selling them for.

This gun show is held in a building I would guess is about 17,000 sq ft so it wouldn't be called large and it occurs 10-11 months a year for the club that I am a member of. There are definitely larger shows.