Will lightening my AR barrel ruin its accuracy?

[DMK]

Will lightening my AR barrel ruin it's accuracy?

I have an RRA 16" non-chrome mid length HBAR AR barrel that I'm considering getting turned down to make lighter. I don't like the weight, but I'm concerned about screwing up it's accuracy. It's sub MOA accurate right now.

I realize that the lighter profile will be more subject to heating up, but I plan on free floating it and shooting it exclusively slow fire with optics.

What do you guys think? Should I lighten it or leave it heavy and work on the arm muscles?

 

[carpettbaggerr]

Sub-moa? Leave it alone. And you can probably get a new upper for what turning your barrel would cost.

 

[ny32182]

If some recent threads are any indication, its a lot cheaper to have the barrel turned down.

If its going to be a free floated scoped bench gun though, I don't think I'd risk messing with it if it already shoots sub moa. Weight on a gun like that is a good thing, especially in the barrel.

 

[DMK]

If its going to be a free floated scoped bench gun though, I don't think I'd risk messing with it if it already shoots sub moa. Weight on a gun like that is a good thing, especially in the barrel.

I didn't say anything about shooting from a bench.


Oh yea, there's no way I could put together another upper for the price of turning or even turning and fluting. Heck, a new barrel alone would cost at least $150-$200 and nobody even makes a lightweight mid length barrel.

You guys are probably right though. I may lighten my chrome lined midlength barrel instead.

 

[wanderinwalker]

Sub-MOA?! Don't mess with it! Screw up something else instead!

Easy enough, eh?

Good luck on whatever you decide to do.

 

[Jim K]

DMK, it sounds like you want approval, not comment, since you are going to do it anyway. Turning down that barrel may cause/release stresses as well as change the bedding. I think it is possible that not only will you not get the same level of accuracy, you may end up with a "bushel basket" rifle.

If you go ahead, let us know the result; I don't like the taste of crow, but I have eaten it before.

Jim

 

[Onslaught]

If it's sub-moa, I guess it could negatively impact it somewhat, but it certainly won't "ruin" it. I've got a RRA middie, (chrome lined though which can be a tad less accurate to start with) and I had it turned down to A2 profile by Steve at ADCO (cost me a whole $55) and it shoots under 2 MOA with cheap ammo. I also had another chrome lined RRA mid-length barrel turned to .830-ish and fluted by Kurt's Kustom, and it's closer to 1 MOA with the cheap stuff.

Specifically with RRA barrels, and specifically dealing with Kurt's Kustom Firearms and ADCO Firearms work, the concensus is that it does not noticeably affect accuracy, but then again, they're all chrome lined, and none were sub-moa to start with.

I asked the same question on AR15.com because right now, mid-length, chrome lined A2 profile barrels are one of the big sellers over there, so the selection to draw my conclusions from are more than a few. Not one person responded that "profiling" their barrel had changed the performance of their barrel.

BUT STILL, I think I'd flute the crome lined one, and leave that sub-moa one alone... Unless you don't care if you turn a .65" grouper into a 1.35" one.

 

[DMK]

DMK, it sounds like you want approval, not comment, since you are going to do it anyway.

Well, no and yes Jim. I will to lighten one of the two HBAR carbines but I do not wish to ruin an exceptionally accurate barrel.

I was initially considering leaving the chrome-lined barrel as an HBAR because I have a red dot on that one and thought it would make a better "blaster". The chrome lining would resist wear more and the HBAR profile would be more resistant to the effects of heat.

However, after the comments here, I think it would be better to preserve the more accurate barrel, lighten the chrome lined "blaster" and reserve higher rate fire to my SAR1 which is cheaper to feed anyway.

Now, the only question is: Send it to Steve@ADCO for a quick A2 profile, or is it woth the wait for a full length Turn and Flute from Kurt?

Thanks for the thoughtfull comments all!

 

[MeekandMild]

Will lightening my AR barrel ruin it's accuracy?

I've been thinking a lot about this question. It would seem to me that if there are hidden stresses in the barrel you might end up with one which warps more easily when it warms up. Also if it has been straightened it might have more tendancy of getting a few mm of dogleg.

So my answer is maybe.

 

[444]

I had a barrel turned down by KKF and it shoots just as good now as it ever did.
Personally, if it was a real good shooter I would just leave it alone. I have no reason to believe that having it turned down would have a negative impact on it's accuracy, but I am a big believer in not messing with stuff that works.
Having a nice light, short carbine is very handy, but let's be honest, an AR15 isn't a heavy rifle to begin with even with a so-called heavy barrel. If you have it turned down, it will be lighter, but how much lighter ? Ounces ? Will that really make that big of a difference ?
I was on a kick a year or so ago of putting together AR15s. For some reason I had to try everything out there. At one point I decided to try to build the lightest carbine I could while using a standard receiver and such. So, I had a barrel turned down. I bought an ACE single tube stock for it. It was lighter, but it wasn't all that much lighter.

Sorry for drfting off topic, but I ask this question every time I see this mentioned: On these internet gun forums it is repeated over and over again that a chrome lined barrel isn't as accurate as one that isn't chrome lined. Ok, if that is the case, how much accruacy are we talking about ? 1/4" at 100 yards ? Less ? More ? I have never yet had anybody answer this question. This fact is repeated every day, but no one seems to be interested in the actual numbers but me.

 

[ny32182]

I too would be interested in the actual numbers, but the problem is that the numbers aren't going to be exact because there is too much variation from barrel to barrel. Any two barrels compared (chrome and non chrome) aren't going to make for a good hard number, because the sample size is so small (one of each). In order to even begin to get an average quantification of the accuracy difference, you are going to need at LEAST a couple dozen rifles from different production runs, chromed an non chromed, before I would personally give any credit to the numbers as an average.

And even if such a test was done, it would still be just that: an average. It could ideally tell you your percentage chance of getting a rifle that falls within a given accuracy range, but it couldn't make any guarantees about what you would personally be getting.

Although, I think experienced long range accuracy competition AR shooters would have the best shot of answering this question based on their experience.

//////////

Back on topic: if the gun shoots 1/2 moa vs 1 moa, or is free floated vs non free floated, that isn't the kind of accuracy difference you are really going to be able to see just shooting off hand with a "field grade" AR.

I wouldn't worry about volume of fire much either. The old A1 profile is very light, and was originally used with a full auto weapon. My own Superlight carbine has been smoking hot and never had a problem. Sure, the groups open up just a bit if you go from a couple mag dumps back to the sandbag right away, but who cares? If your rifle is that hot, you are already in "volume fire" mode anyway, and pinpoint accuracy isn't likely to be much of a concern. JMO, YMMV, and all that.

 

[444]

Well, let's not get too far caught up in this. I am not looking for a triple blind super scientific test with no room for error. Basicaly what I am looking for as a gun owner is: Would I be able to tell the difference ? Of course then we have to get into what my uses of the rifle or carbine are and all that, but again, that is taking it beyond what I am interested in.
Let's do it this way:
Would a serious bench rest shooter be able to tell the difference ?
Would a serious Highpower shooter be able to tell the difference ?
Would a causal varmint hunter be able to tell the difference ?
Would a guy that likes to shoot groups on paper and work up handloads be able to tell the difference ?
Would a guy that shoots beer cans out on the back 40 be able to tell the difference.
I think one of those catagories should narrow it down for a rough gauge. Most important is, has the guy answering the question actually done it, or is he guessing based on something he read on the internet ?

 

[Sunray]

Rule number one. If it works, don't fix it.

 

[artherd]

Sub-moa? Leave it alone.

Second that, if you have a SUB-moa AR barrel, don't touch it.

Get a new upper and do A2 on that. Maybe play with fluting (but be careful the fluting is done at the right stage, or you're better off withought it. Get someone like Mike Rock involved.)

 

[pbhome71]

What if I have to get another barrel?

Not to hijack your thread. Does anyone know of any source that provide a good light-weight barrel?

I have a Dissipator upper (16" HBAR with full length guard), which I like. However, it feels a little front heavy for me. The only light-weight barrel that I can find is a carbine 16" with CAR hard guard, which I really don't like.

Thanks,

-Pat

 

[DMK]

Does anyone know of any source that provide a good light-weight barrel?

AFAIK, nobody makes a lightweight midlength barrel. If you want a light weight factory barrel you have two choices: a) Superlight 16" with the short CAR/M4 gas system from Bushmaster or Colt (Not even sure if Colt still makes one) or b) 20" A1/SP1 profile from Fulton Armory or CDNN has some pre-ban lightweight Colt uppers.

Adco sells a midlength with an A2 profile (turned down under the handguards and heavy from the sight to muzzle) Bushmaster sells the same profile in a 20". Either of thos options is available pre-or post ban.