Re-Profiling AR barrels

[Sam1911]

I'd like to hear your experiences if you've had an AR (or other) barrel re-profiled.

I'm vaguely considering having a standard contour 16" midlength AR barrel turned down to a lightweight or featherwieght profile by AR15Barrels.com. The plan would be to reduce both the diameter behind the gas block (now about 0.625") and between the gas block and muzzle device shoulder (now about 0.715") down to 0.550" or so. That's only around $30, and they'll park it all again for me for another $40. Sounds like a pretty slick way to get a lightweight barrel, but I'm not sure how much I want to do this.

So, if you've had this done, what was the weight savings? Did the accuracy change? Would you do it again?

And more generally, I'd like to hear any ideas you've got about lightweight AR barrels. Aside from an expected bit of wandering as they heat up, how do they work for fast carbine shooting, such as tactical classes and matches? Would you go that light or not? (The rest of the rifle will be modestly light, and will use the new MI 15" lightweight tube.)

 

[MistWolf]

Heavier barrel controls heat better and will generally last longer. Lighter barrel may wear out quicker but generally handles better. Barrels are wear items but even a light barrel should last several thousand rounds, barring abuse. By the time you do need to replace the barrel, you will have learned something and the cost will be a drop in the bucket compared to what you spent on ammo.

Before re-profiling the barrel, look to see where else you can cut the fat first. It makes no sense trying to save weight with a thinner barrel if the rifle has heavy handguards, stocks and accessories weighing it down

 

[rcmodel]

My old Colt SP-1 pencil barrel carbine is still one of the most accurate AR's I've ever owned.
Cold, or hot.
Makes no difference.

My experience with turning down barrels has been about 50/50 mixed.

Years ago, I got free match rifle .30 cal bull barrels out of the AMU scrap iron barrel.
Douglas & Bliss Titus air-gaged match barrels after one season of match or Vietnam sniper use.
They got re-barreled every year and the old barrel went in the scrap iron barrel!

I cut them ahead of the throat, re-threaded & re-chambered into .308 light Sporter weight barrels for use on Mauser actions.

Some of them turned out very accurate, and some of them wandered like a drunk sailer when they got hot.

The general consensus among the more experienced rifle armorers was that turning them down released pent-up internal stresses that never showed up as full dia heavy barrels on target rifles.

They were stress relieved after boring and rifling when made.
And turning them down set up new internal stress in some of them that changed POI when they got hot.

Sounded reasonable to me at the time.
Personally, I think you pays your money, and you takes your chances when re-contouring a heavier barrel.
At least that was my experience.
But I was getting the barrels free, so I wasn't paying my money to find out.

I think in the long run, you would be better off selling your barrel, and putting the money on a lighter barrel like you want.


BTW: I thought AR15Barrels went belly up a couple of years ago?
You sure that isn't just the old website popping up?

If they are still in business, let me know!

rc

 

[bullzeye8]

Wouldn't it be better to just flute the barrel if all you want is weight savings. I know they say a fluted barrel is better than a thinner barrel of the same weight so I would spend the money to get it fluted before you re-profile.

 

[Sam1911]

I'm not sure if they're in business or not. Their website does say they're only doing re-works of customer supplied barrels, but whether they are active now I can't say.

The build will already be pretty light, and I don't think this is necessary by any stretch, I just figured maybe I'd consider it while I'm waiting on some parts I need to finish it up.

I do believe I'd rather get it together and see how it shoots before I decide to do anything drastic. Unrelieved stresses are a concern.

Thanks guys!

 

[dprice3844444]

check barrel contours at green mountain barrels
http://www.majorpandemic.com/2012/01/jp-enterprise-ar15-barrel-kit-review.html
http://www.jprifles.com/1.4.5_hs.php

check out the thermal dissapator
If you opted for the JP Thermal Dissipator, it attaches to the thinner barrel profile between the gas block and receiver. The Dissipator increases barrel stiffness and provides 700% more surface area and seven times the cooling of a standard barrel profile, increased barrel life and accuracy, and improved heat management for more comfortable high rate shooting. Because of the heat dissipation abilities, heat distortion is limited and barrel temperatures are controlled even during sustained firing. The Dissipator is available for .650” and .750” barrel profiles in black, red, blue, and white anodized finish and will fit other barrels with those profiles. The red looks sharp peeking thought he handguard. Seems like someone should have taken this queue from the electronic industry and installed heat sinks long ago

 

[taliv]

if randall isn't taking new work, there are other options. this guy used to do a brisk business of reprofiling and dimpling barrels https://www.adcofirearms.com/

 

[Sam1911]

Cool guys, thanks! Much to think about, probably for use in the future.

 

[Sam Cade]

I used Adco a couple years ago to turn down a HBAR.

No complaints.

 

[Sam1911]

What did you think of the accuracy before-vs-after? Any released stresses problems?

 

[Howard Roark]

I've turned a few SR profiled barrels down to more our less M4 profile. One shot 1/2" groups at 100 yards. I would imagine that they all will.

 

[Sam Cade]

What did you think of the accuracy before-vs-after? Any released stresses problems?

About the same. It wasn't a very good barrel and was only shooting roughly 2 MOA before I sent it off and it didn't get any worse.

 

[AR15barrels]

BTW: I thought AR15Barrels went belly up a couple of years ago?

If they are still in business, let me know!

I'm still in business.
I'm even doing barrel work fulltime now.
Anyone saying otherwise is simply uninformed.

 

[AR15barrels]

if randall isn't taking new work, there are other options.

I only do service work now.
I'm no longer SELLING parts or making custom barrels from blanks where I have to provide all the parts.
Most of my work is re-work of existing factory barrels.
I will turn/chamber barrels from customer provided blanks/parts.

 

[Sam1911]

Hi! And thanks for dropping in! Really appreciate it!

in your experience, how much weight would be dropped going from a standard middy 16" to the lightweight contour?

(My rifle's together so this is probably academic, but I could certainly be tempted!)

 

[jmorris]

I have turned a few, most of them making 18" barrels for 3 gun. You could buy one ready to go from JP for less than what I would charge to do one.

 

[henschman]

I am getting ready to do the same to my A4's barrel... I'm having it turned down to 0.57" forward of the gas block to basically give it an A1 profile, save for the gas block journal. I am planning on sending mine to Adco, who will do the job for $65 including re-parking.

I have a rifle with a BCM 16" lightweight middy upper, and it s a fantastic little rifle. I have a free float handguard on it, and it will hold 2 MOA with M193. I have got it pretty hot before, like going through 40 round strings of fire pretty rapidly with it, and have not noticed any appreciable decrease in accuracy for the type of shooting I do, which is exclusively from field positions. No, it's not a very good sniper rifle, and wouldn't do very well in a bench rest competition, but I'm going to go out on a limb and say you're not planning on doing that type of shooting with a lightweight fighting rifle. Buf you just want to be able to hit torsos out to 500 yards and heads out to 200, and be quick on target in close quarters, a pencil barrel carbine would be just the ticket. I just used mine to win the Zombie Run 'n Gun down in Texas earlier this month.

 

[rbernie]

I'm not a fan of the pencil barrel AR craze. Yes, I've had 'em. Yes, I carry my ARs in the field hunting, for miles and miles and miles a day on foot. And no, I'm still not sold on the idea for use in the field.

For me, and perhaps only for me, I find that the carbine handles best when it balances neutral to muzzle heavy when held by the receiver ring/delta ring. It comes up smoother to the shoulder, tracks moving targets MUCH better, and settles in the offhand better for snap offhand shooting that still requires precision (not just a hit somewhere on a target, but a clean heart-lung shot at 50-90 yards offhand).

Front-light carbines do feel swoopy when you just handle them, and light is nice when you're carrying the carbine for hours. But still - I've sold most all of my pencil barrels (still have one vintage CMMG 16" pencil barrel that's scary accurate) and moved to mid-weight offerings.

 

[taliv]

I only do service work now.
I'm no longer SELLING parts or making custom barrels from blanks where I have to provide all the parts.
Most of my work is re-work of existing factory barrels.
I will turn/chamber barrels from customer provided blanks/parts.

awesome! that's very good news!

 

[dprice3844444]

http://www.fulton-armory.com/barrelfa16m4gicontourcm1x9threadedchromelined-1-1.aspx

16 inch ar-15 1/8 pencil barrels made by criterion chrome lined

 

[Welding Rod]

Adco turned down a RRA 20" chrome lined HBAR for me. They did a nice job. Refinish and reassembly looked good. Turn around was fast.

I haven't done testing for accuracy yet though. I plan to mount a free float forearm first to eliminate forearm pressure from the equation. It was a MOA shooter before being turned.

 

[jerkface11]

My dad had adco turn a barrel down for him. Accuracy stayed the same and the point of balance moved from 2/3 down the handguard to just in front of the magwell.

 

[DougW]

I had a 20" HB (Wilson chrome moly) turned down reducing the weight by exactly 1 pound. It is on my A2, and is one of the most accurate AR's I have.

 

[Sam1911]

For me, and perhaps only for me, I find that the carbine handles best when it balances neutral to muzzle heavy when held by the receiver ring/delta ring. It comes up smoother to the shoulder, tracks moving targets MUCH better, and settles in the offhand better for snap offhand shooting that still requires precision (not just a hit somewhere on a target, but a clean heart-lung shot at 50-90 yards offhand).

Well, mine came out at 6 lb. 6 oz. (without optics) and balances about 1/2" back from the front of the mag well. So I'm pretty tempted to leave it alone.

 

[jerkface11]

I don't think I would mess with that either.