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Barrel Accuracy issues

5K views 24 replies 10 participants last post by  Destry 
#1 ·
I bought a 18" 6.8 barrel and can not get it to shoot as advertised. I have tried 95 gr ttsx 110 gr vmax and 120 gr sst. I have tried H322 and AA2200 doing optimum charge weight load development with each powder with each bullet. I played with seating depth from 2.260-2.295 in .005" increments. I have also used 2 scopes to rule out scope issues too. I took the muzzle break off and shot it without. I also looked at the crown using a magnifying glass. The gun is gassed right as the brass is landing at 3-4 o'clock. I even bought some factory hornady ammo just to see what kind of difference it made and I was getting 3" groups using that. I have put close to 200 rounds through this barrel trying to get it to shoot something half way decent. The best group I got was 120 gr sst over 27.2 gr of 2200 with OAL of 2.285" and that was a little over 1.5" group. I shoot off sandbags to ensure the best rest I can. I have several other ar's not in 6.8 and all of them will shoot under MOA with a couple of them shooting 1/2 MOA. Also, trigger is a crisp 2lb trigger. I have been working with the manufacture with this issue and they are very helpful and easy to deal with, I'm just trying to figure out what it could be as I've built a bunch of ar's using several different barrel makers and have never had this hard of a time trying to get a barrel to shoot that was guaranteed match grade accuracy. As of right now I sent my complete upper to the manufacture for them to do some testing on it. Just curious if anybody else has had this problem and was it a bad barrel that needed replacing?
 
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#6 ·
I guess i missed that in the original post. The only time I have run into that was with a gas block that was a little too tight a fit inside the hand guard so it would hit when the barrel whipped. Hopefully they will figure it out.
 
#8 ·
have you tried a good copper cleaner in the barrel? maybe you have copper fouling?
 
#9 ·
Some times it's nothing more than a false reading on the torque wrench when the barrel nut seizes on the receiver. If the barrel nut ever squeaks when installing stop right there and grease it up. I take the upper completely apart and rebuild and it shoots fine second time around. Crowns should be inspected with a 10-20X loop, all it takes is one little burr on the side of 1 land.
 
#13 ·
A friend of mine bought an expensive high end barrel, installed, it, put on the muzzle device and found that after the first few Sub MOA shots it started shot gunning at 2-3 MOA with 4MOA flyers. He checked "everthing" including checking barrel torque twice and bedding the extention on the third time around. Then he called me and I asked if he'd pulled the muzzle device and checked the muzzle and crown. He hadn't. We checked and using a lope, as Constructor has suggested here, found a small chip was missing from one land right at the end of the muzzle. It doesn't take much and it was very hard to see, being we're both old and blind, eith the naked eye. Brownells replaced the barrel and accuracy returned to sub MOA immediately.
 
#14 ·
Good news, I talked with the manufacture today and the person I talked to said that they replaced my barrel due to accuracy reasons but he didn't know what the reason was as they just shot it and seen that it wouldn't shoot and decided to replace it. Even better news is they test fired the new barrel to ensure accuracy and he said the 2 test targets were 3 shot groups with one being less than 1/2" using 110 gr bthp. So I feel confident I can find a load it likes using my preferred 120gr SST!
 
#15 ·
FWIW, I've never been able to put 10 rounds of my 6.8 handloads into half an inch at 100 yds (approx. 1/2 MOA), even though others here (rifter, et al) definitely can. Its not the fault of the several barrels (WOA, BHW and ARP) I used, instead I attribute my performance to my home-building and handloading practices and my less than perfect shooting skills.

For some reason, I find the .223 round to be much more accurate, perhaps because the rifles are heavier and the recoil slightly lighter. I don't have any 10-round, 1/2 inch .223 targets yet, but I'm getting close. For my 6.8s, my standard of excellence is 10 rounds into 1.25" at 100 yards, more than good enough for hunting and defense purposes (an unlikely event in any case). It may be that the smaller the bore, the better the potential for extreme accuracy. I note that benchresters have long since settled on 6mm rounds for their game. - CW
 
#16 ·
FWIW, I've never been able to put 10 rounds of my 6.8 handloads into half an inch at 100 yds (approx. 1/2 MOA), even though others here (rifter, et al) definitely can. Its not the fault of the several barrels (WOA, BHW and ARP) I used, instead I attribute my performance to my home-building and handloading practices and my less than perfect shooting skills.

For some reason, I find the .223 round to be much more accurate, perhaps because the rifles are heavier and the recoil slightly lighter. I don't have any 10-round, 1/2 inch .223 targets yet, but I'm getting close. For my 6.8s, my standard of excellence is 10 rounds into 1.25" at 100 yards, more than good enough for hunting and defense purposes (an unlikely event in any case). It may be that the smaller the bore, the better the potential for extreme accuracy. I note that benchresters have long since settled on 6mm rounds for their game. - CW
You are correct, you must shoot an AR different than a bolt gun and must shoot a lightweight heavier caliber AR different than a 223 if you expect to get good results.
 
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