Problem child barrel

[BillB]

I have a barrel on a 6.8 build that just absolutely refuses to group anything I feed it, the best I can seem to get are groups anywhere from 2" at 100 yards and those are rare with the more common sizes being around 5" or 6", or worse, and always, always have these wild flyers (usually several) that will impact nowhere near where the rest are hitting.

I've really tightened up my reloading technique and even tried a different brand of dies. I've tried 6 different powders, 5 different bullets and weights, different brass and about the only constant is the CCI41 primers which is basically all I have.

I had shot about 400 rounds through this thing trying to get it to perform( not looking for sub MOA groups) with any degree of consistency and had not given it a thorough cleaning so I did that with hope. My hope was dashed when it continued to shoot very erratically, 2 or 3 shots looking like they might make a decent group and then 2 shots 6 or 7 inches away, every damn time, or they're all just all over the place. Another 2 or 3 hundred rounds and I took off the muzzel device, easy since it's just a Vortex FH and looked in the bore at the muzzel, the tops of the lands were covered with copper so I used some CR-10 and decoppered it. Off to the range, first group was 28.8gr of LT-30 under a 90gr Gold Dot, my best load from the last trip, and it was decent but still nothing to be proud of and then everything afterward was crap again.

Tonight I took off the FH again and all of the copper is back, just like before. Now, if copper deposits in any rough spots, and it's all over the tops and edges of the lands that means the rifling seems to be in pretty rough shape no? Also, there are sections of some of the lands which are not coated with copper and then there is long sections that are, like there are really deep defects in the surface of the lands. Is this what is or could be causing the ever present flyers and very poor accuracy?

There is no copper wash in the grooves or along the edges of the lands like I normally see in barrels, just all down the tops of the lands as far as the flashlight will light and as far as I can see.

Please, any thoughts on this? This barrel has done this since day one and I'm tired of wasting powder, primers and bullets trying to get this thing to shoot. Honestly, I'd be ok with 2" at 100 yards if I could get it to shoot 2" groups at 100 yards every time, or even most of the time.

[boss_hawg]

Care to mention the manufacturer? Do they make a claim or guarantee on accuracy? Do they have good customer service?

Also is the rest of the build to spec like upper, barrel nut torque etc? That’s a basic question and it sounds like you’re miles beyond that but something to check if you didn’t build it yourself.

[DG23]

Good borescopes are not that expensive.

I don't personally try to get all the copper out of my 'good' barrels. Copper Equilibrium is real and for me that accuracy tends to stick around for a while before degrading and some copper needs cleaned out.

[Jsp10477]

I’d ditch the barrel and move on. Good 6.8 barrels can be had for about $200. It sounds like you’ve given that one a fair chance.

[NWcityguy2]

There are things which can be done to help improve an average to good barrel. There is nothing that can be done to improve a trash barrel.

Buying a bore scope to find out why your barrel is bad would be an academic exercise in the truest sense in that ;it would cost money, you might learn something, and you would still be no closer to solving the problem.

AR Performance still has 6.8SPC barrels in stock.

https://ar15performance.com/6_8_barrels

[BillB]

No claims to accuracy but they do state that they perform as good as so called match barrels for less money. The bore is melonited in vase I forgot to mention and it makes any difference. No, I dont want to disclose the maker but I've heard they do have good customer service but when I'm on the 6 8 forum and have laid out the troubles I've had with it they're kinda like a pack of wolves and they all pile on saying it has to be something Im doing wrong because it just couldn't be the barrel. Well, I dont know what else to try and with ammo and reloading supplies being how they are right now I just dont want to continue to waste what I have.

I built the rifle myself and like every other AR I've built, it functions 100 just without the fun of it being accurate. With the barrel I also got a matched bolt, though the headspace measures outside the specified range for the spec2 chambers. I just have to set up my resizing die s to allow for the overage. I do not buy low budget components when building rifles either, I know all the correct torque specs, where and when to stake, and I do it, gas blocks pinned. Components used come from BCM, Geissele, Vltor, Sprinco, Forward Cintrols Designs, B E Meyers, Centurion Arms....... like that and I never deviate from these trusted ( by me) brands because theyve yet to let me down.

Honestly, I've never encountered anything like this and I'm gonna try to post a pic or 3 of what I see, its gonna be tough to do. and see what some other think may be the goings on but if copper deposits in any rough areas in a bore then the lands of this barrel are junked.

And no, I have not talked to the maker yet, that's why no name, and tell him what's going on, even though he is probably fully aware already of the issues I'm having, he follows the forum pretty closely I think. I'll see what he says or what hes willing to do. I've heard the guy is pretty abrasive though.

[Jsp10477]

If it’s who I think it is, I’d imagine you’ll be taken care of. He’s a member of this forum as well.

[crosseyedshooter]

To rule out your reloads, is there the equivalent of FGMM for 6.8? It seems universally accepted for 5.56 and 7.62, if it doesn't shoot well with FGMM, it's basically a bad barrel. What's the standard for accurate ammo in 6.8?

[NWcityguy2]

It sure sounds like an AR Performance Barrel, given that they sell bolts to match and are super popular with 6.8 SPC shooters. I have one of their barrels on my main AR and it has been great. But...

Welcome to the world of having trouble with a product that other people like. I remember buying a bolt action rifle that shot a dozen different loads 3-4 moa. One person told me I shouldn't be complaining without chronographing it first and another person said that I should be happy because it shoots literally one bullet well. But I digress...

If the bore is nitrided, you aren't going to be reconditioning it in any meaningful way. It is what it is.

Talk to the maker and see what they can do, or move in a different direction. Continuing to experiment a barrel that throws bullets completely off the target is "throwing good money at bad money".

[NWcityguy2]

To rule out your reloads, is there the equivalent of FGMM for 6.8? It seems universally accepted for 5.56 and 7.62, if it doesn't shoot well with FGMM, it's basically a bad barrel. What's the standard for accurate ammo in 6.8?

How much does that really help a reloader?

[BillB]

Well, I dont think hes in the business of making crap barrels, he has a fanatical following and believe it or not I emailed him during my lunch today hoping to reserve a 12.5" barrel that's due some time in October. So no, I dont think he is doing bad business. $#!+ happens, I understand that and have no I'll will towards the man, if I did I sure as hell wouldn't be trying to get another one.

The just of my OP was simply to ask if the copper deposits on top of the lands was normal, I've never seen it happen, it's always along the edges down in the grooves or just a wash of copper filling in the roughness in the grooves, maybe some at the muzzel. And if this copper in the obviously very rough lands could be causing the poor accuracy and extreme flyers I get constantly.

[BillB]

I'm not sure if there is a "gold standard" 6.8 loading but I have shot some Hornady 110gr BTHP loads through it, but some cheap bulk H and higher end 110gr V-max load and their 100gr GMX loading and basically the same result. So, I dont know. I'm no reloading genius but I only use a single stage, take my time, prep is king, quality components. a multitude of powders, bullets and seating depths. S&B cases sized for my chamber minus .004". Been using Lee dies but just bought a set of RCBS to see but I've always had Lee dies for other calibers and had success with them. Anything is possible though I guess.

[Coal Dragger]

If both decent quality factory ammo, and carefully assembled reloads aren’t working then there’s probably not much to be done.

The fact headspace is a bit excessive is a big red flag that there is something wrong. Some barrel makers have issues with salt bath nitride barrels and barrel extensions, depending on the procedures used when assembling them it’s possible the barrel and barrel extension to loosen from specified torque.

Good luck.

[NWcityguy2]

The just of my OP was simply to ask if the copper deposits on top of the lands was normal, I've never seen it happen, it's always along the edges down in the grooves or just a wash of copper filling in the roughness in the grooves, maybe some at the muzzel. And if this copper in the obviously very rough lands could be causing the poor accuracy and extreme flyers I get constantly.

I honestly don't pay attention to copper fouling enough to say yes or no. I tend to notice it by the muzzle myself. To me, it seems like a good question for ARP.

[Glacierwolf]

I am a reloading instructor and former US Coast Guard National Shooting team member. I do not usually post - way too much AR reloading dis-information. Usually from bolt gun shooters.

400rds. Your barrel and new upper is barely broken in. Sounds like you have done right so far. The key to your issues - those flyers - you get a nice group going - X,10,X,10,X and then one shows in the 7 ring. Assuming the barrel nut is 35ftlbs (I have gone to 87ftlb to get the right fit and that rifle was a tack driver) and you are a competent marksman this is always and ammunition issue. Go buy a coaxial concentricity gauge and check your ammo. In EIC matches were ammo is issued I will quickly run all the ammo - .000" to .003" true are my 600yd slow fire, .004" to .008" are my 300yd, .009" to .015" are 200yd slow fire. Anything past .015" become sighters. I have found Lake City Match at .027" and got a Federal Gold Medal that was .047". Saved those as training aids.

Your ammo has to be totally identical from round to round. I teach people to process all their brass in batches. This way you have a pool of 500 or so rounds that even if something is a tad kittywampus they are all kittywampus the same way. All brass with the same headstamp. Then you sit down with primed brass, cal the scale - and spend the rest of day assembling rounds. Digital scale+powder measure will make the job much easier and more accurate. You want RCBS match dies - or just buy the match seating die since you have the other. That match die will make sure the bullet is aligned with the brass to make your ammo all in the .000" to .015". It will also let you adjust each round so they are identical length. This is another important metric - identical COL. Longer rounds are going to have a shorter jump to the lands and grooves. Shorter ones get more of a running start at the rifling - and will come out faster, and faster means it hits a tad higher.

Another tool to consider. Chronograph - you want to see all those rounds come out at nearly the same speed + or - 30fps for 600yd competition. I have made loads that were 2.1fps for 10 rounds. You get them to all come out the barrel the same speed and still have those flyers - then you look at concentricity issues.

Me? I would loan you a chronograph first to check speed and everyone was coming out the the barrel at the same fps. Fix that first. Then match dies to kill those really big flyers. Then the coaxal gauge to put your ammo into groups.

Hope this helps.
Kevin M

[Fast Pat]

I think something is loose. Either the barrel or the scope/mounts if so equipped.

[BillB]

Nope, checked both and both were tight, loosened, torqued to spec, again.

I bought a borescope and I'll post pics or a video later.