My 6.8SPC shoots like crap. Help.

cjdavis618

New member
I have a Model 1 sales 16" 6.8SPC upper that I bought from a guy and the thing doesn't group worth a flip. At 25 yards with a eotech, I was getting about 3-4 inches.

It does have a flash hider on the end and there is lots of buildup on the crown. I have cleaned all of that off and haven't been back to the range. Would that have affected the accuracy that bad at such a short distance?

I am using hornady 110gr Ballistic tips on it and haven't started hand loading for it yet. I'm just wondering if I should even bother. I also know that the iron sights on the upper are not lined up either and the front sight is on a "Tri" rail mount on the barrel. It looks crooked, but I haven't attempted to straigten it out. I plan on using the Eotech/scope on the rifle.

I have other ARs and all shoot well. This one shoots like wore out musket. I need some pointers.

Chris
 
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Get a bottle of Sweets or CR-10 and follow the directions.
If the crown was filthy, the barrel's likely full of copper to the gills.

Model One Sales uses E R Shaw barrels on most of their uppers, and those are usually real accurate.

Quote:Would that have affected the accuracy that bad at such a short distance?


Outside the crown? It wouldn't have any effect.
 
model 1 still uses the spec 1 6.8 chamber along with the faster twist that the hordady ammo may not care for. Might be worth it to pic up some silver state armory ammo.
 
I have heard terrible reviews about the Hornady 110 vmaxes in the 6.8 Try a different ammo, like what the previous poster said.
 
Please be careful with the advice offered.

The twist rate on the barrel that M1S sells is the 1/9.5 twist, which is way faster than the 1/11 being used as standard now. The 1/10 and 9.5 is for the .270 bullets, which are common at 130 grains and up.

To stabilize the 110grain or lower, you need the 10, 11 or 12 twists. Also, if you purchase SSA ammo, you will have to buy the Commercial ONLY.. your barrel is not manufactured to withstand the increased pressures of the Tactical loads.

Stay with the 130 TSX (barnes loads), or the 130 Remington loads and your rifle will pick up some accuracy. Honestly, spend $200 bucks or more and pick up a Bison Armory Stainless Steel barrel and replace that 1/9.5 barrel. Take it to the recycle bin. It's not worth anything in 6.8caliber. I hate that M1S still sells that junk and sadly that people buy it without further research into the round. Even when Remington developed the SPC round with SAAMI chamber they chose 10 twist, not 9.5.

Not meaning to burn the OP, but take a little time at 68forums.com and read up on the twists. There's a reason that CMMG, Bushmaster, Armalite, Rock River, Stag (all commercial vendors of AR type rifles) now stock their 6.8s with 1/11 twist barrels. The only two that still do not are Ruger and LMT. There's a reason for that!
 
I would say that EL has a good starting point, i would clean until the barrel was so shiny you couldn't look through it and clean the gas tube as well.

Was the eotech on it when you bought it, if so it hasn't been taken care of either. Go back to square one and clean/fix everything you can think of and maybe try a different scope.

The model 1 shaw barrel is a good barrel, however model 1 uses a fast twist, (1/9.5) and they do have pressure spikes with some ammo, that doesn't help groups either. Look at the pressure range of the ammo your using or load some of your own with a lower pressure powder.

That barrel will make decent hunting groups and the 6.8 doesn't need to be loaded hot to work right. The hotest i load mine to is about 2700 and no game has gotten back up yet.

You can learn the history of the 6.8 by just typing in 6.8 or 6.8spc, or go to 68forums.com, as a last resort you can recrown it as well. blue

 
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I have had that same Model 1 upper in 6.8. Evil is likely correct. Get the copper out of the barrel. It has been my experience that the Shaw barrels are a bit rough and tend to gunk-up pretty quick. Mine, as well as the several dozen others that came through our shop all shot the 110gr. Hornady just fine. A faster twist will stabilize the V-Max just fine.
John
 
Update to this thread,

I did clean the barrel and got all of the fouling out till there were no more colored patches, but the crown buildup wouldn't release. It still shoots like crap with that hornady ammo and I did get the reloading supplies for the 130gr and it works much better. It will do about 3/4" groups at 100 now with little trouble. I still am working with the load but range time has been limited.

I also re-crowned the barrel to remove the buildup just to be sure. I will be replacing the barrel in it soon for the SPC2 with 1:11 twist but the Hornady 110 still throws wild groups even at short distances with this barrel. Not a good combination. I suspect there may be a problem with the ammo as well. I was able to get 4" groups at 50 yards this time with a 4x scope.

Brandon Sneed, I had no idea that 68forums existed to research before I purchased this upper. I bought this upper used at a gun show with the intention of using it for deer and hogs. I didn't research anything about the caliber or specific parts for it prior to that, other than I knew 6.8mm was another contender for a military cartridge and that is was short range but powerful. I have not committed to memory, all twist rates from all calibers yet.
wink.gif
(Even if I did, the barrel wasn't marked as such and doubt the seller even knew.)





 
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The EoTech is a combat sight, its a good quick acquisition optic but precision is not it's game. Put a scope on it, buy a box of factory Remington OTM (Open Tip Match, I believe this is 115 Gr.) and establish a starting point (control group). The trigger on most standard ARs are poor at best (once again combat components). Don't worry about the sights (easy fix) until you know if it will shoot well enough to meet your needs.
 
Thanks for the help, but I have a 4x scope on it now and I am grouping well enough with a different hand load. The Hornady's that I have that were 110 grain do not work with that barrel, and may not work with any barrel for that matter.
 
Originally Posted By: cjdavis618Update to this thread,

I also re-crowned the barrel to remove the buildup just to be sure. I will be replacing the barrel in it soon for the SPC2 with 1:11 twist but the Hornady 110 still throws wild groups even at short distances with this barrel. Not a good combination. I suspect there may be a problem with the ammo as well. I was able to get 4" groups at 50 yards this time with a 4x scope.

Brandon Sneed, I had no idea that 68forums existed to research before I purchased this upper. I bought this upper used at a gun show with the intention of using it for deer and hogs. I didn't research anything about the caliber or specific parts for it prior to that, other than I knew 6.8mm was another contender for a military cartridge and that is was short range but powerful. I have not committed to memory, all twist rates from all calibers yet.
wink.gif
(Even if I did, the barrel wasn't marked as such and doubt the seller even knew.)



Thanks for the update. As I prefaced, I wasn't trying to burn you at all. I could have been more tactful, however, I've noticed that a lot of folks that have bought the same rifle have had issues... and the 68spc round is becoming so popular that a simple search for Model 1 Sales will come up with info on the 68board.

Anyway... I digress again. Good to hear you got the barrel recrowned, but still no good results. You will find good results with a good barrel, twist and groove. If you're interested, I'll post a review soon as I get the barrel, but Black Hole Weaponry, a sponsor here, offers 6.8SPC barrels, 16" in carbine gas length, and 18" in midlength gas. Honestly 16" needs a midlength for dwelling time, but with the new twist/groove ratio that Carl is using, I've yet to determine the difference in velocity or accuracy by changing the system...

Regardless, the 110gr VMAX is not a match bullet, and unfortunately, in this caliber, not a great bullet at all.. handloaded, you might get some accuracy in the 1/11" twist barrels, but highly doubt better than 1.MOA... I shoot the 95gr TTSX for hogs, 1MOA out of an 18" barrel, and the 100gr Accubond (these are tipped, ballistic style bullets mind you, similar in design outwardly as the VMAX, hence my recommendation), and get around .50-.75MOA out of my 11" twist barrel with the AB. I'm very fond of that bullet. The Sierra Prohunters, 110gr, will do the same out of my barrel, and the same out of my previous 16" barrel also. Bison Armory, WOA and Wilson Combat i've used their barrels thus far, and was very pleased. They offer the 4 and 6 groove 11 twist, and Carl at BHW is offering the 3 groove... which is why I'm interested and willing to test for him the results. I anticipate great results, and will keep you updated if you'd like.

Another question: do you plan to handload, or just buy factory? If you buy factory, SSA is really the only game in town... however, there are others starting to get in the game, and the prices will subsequently come down. Hornady and SSA are the only ones with brass for the small primers as well. Large not so much.

Elite Ammo will be providing some ammo on the market soon as well. Good luck with your 6.8 and keep us posted.
 
No problem Brandon, Thanks for the reply.

I am planning on handloading and the load that I am doing well with right now is with Nosler 130Gr Btips and, CCI200 primer and H335 powder. I'm loading as far out as I can in the mag well and results are not to bad.

I would be interested in your test results. I am looking for a light carry rifle that I can use multipurpose. 18" or 16" doesn't really matter, but looking for a lighter barrel that is threaded. At some point I am going to use some subsonic loads and a suppressor. Just waiting on the stamp.




 
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I have a RRA upper with a SPC II chamber, and 1:10 twist barrel.
I struggled with 110 gr. VMax bullets, too. I finally got
a load that shoots an average of 1.5 MOA. Good enough for CQB
ammo. For coyote hunting, I have a load for the 90 gr. Sierra
HP bullet that shoots sub-MOA. When I work up a deer load,
it will be the 95 gr. TSX.

The Hornady 110 gr. VMax is just not an accurate bullet.
I have loaded it for both the 6.8 SPC, and the 270 Win.
The 270 Win is a Rem. Model 700 that will shoot most handloads
sub-MOA...Not the 110 gr. VMax. I have tried a number of
different powders, primers, and powder charges...About 1.5 MOA
is the best I have gotten.

From my research the faster twist barrels are accurate, but
velocities achieved and still be in the safe pressure zone
are disappointing. I probably just need to shoot mine a
bunch, burn out the barrel, and re-barrel it with a new
chamber and a 1:11 twist barrel. But for now the SPC II
chamber and the 1:10 twist barrel make a fine coyote rifle
with the 90 gr. Sierra HP load.

Squeeze
 
I have the RRA upper with the 10 twist topped with an eotech and 3x magnifier...I am getting under an inch at 100 with the sierra 110 prohunter and benchmark. I also could not get the vmaxes to shoot.
 
I have shot many fine groups with the 110gr. V-Max in 6.8 SPC, .270 Win., and .270/08. Many, many small vermin have met thier end with that bullet from my rifles. I have never found it more sensitive to loading than any other tangential ogive bullet. That being said, my favorite light weight .270 bullet is the 110gr. Pro Hunter.
John
 
If you are planning on keeping the flashhidder on it, you can drill out the opening wider to avoid the false crown build up on it so quickly. It also makes it easier to clean the build up on the crown when cleaning you rifle.
 


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