Barrel Reprofiling - Disadvantages?

[rpmwfo]

I am thinking about reprofiling the barrel on one of my AR's that I want to use for 3 gun. It's currently a 20" that is .880 under the forend, and .725 in front of the gas block. Are there any disadvantages to thinning it to .750 under the forend? The guns shoots great now, but was looking to trim a little weight and make it handle a little quicker.

What are the disadvamtages? Think it will wreck the accuracy over long strings of fire? I also use it for busting praire dogs occasionally as well.

Thanks.

[Patrick Sweeney]

The only problem to getting it done is finding someone with a lathe big enough, who won't have an attack of the vapors when you tell them it is a rifle barrel. You'll have to remove the barrel from the rifle, and probably the front sight assembly.

As for accuracy, that one was answered a long time ago. Guns & Ammo, back in the early 1970s fitted match bull barrels to a pair of Mauser rifles. They then shot them for accuracy (a .22-250 and a 270 as I recall) and then lathe-turned them down. They did it in .100" increments, shooting after each reduciton until they had pencil barrels, and found accuracy was just fine. One of them even shot better as a pencil barrel than it had as a bull barrel.

The trick, as with all things, is in the quality of the work. If you have some hack do it, with a worn lathe and heavey-handed and dull tools, he'll bend your barrel.

The economics might not work out. For the cost of all this, might you simply replace it with a lighter barrel?

[rhino]

Kurt's Kustom does this all the time and it's significantly less than a new barrel.

KKF

Edited February 16, 2005 by rhino

[Patrick Sweeney]

OK then. I hadn't looked into getting it done for over a decade, so I didn't know what the general cost was. And if he does it on a regular basis, he probably has figured out how to do it without taking the front sight off.

Rhino, you are a veritable font of knowledge.

[rhino]

Rhino, you are a veritable font of knowledge.

Either that, or I was reading the AR15-L Yahoo! Group back when everyone realized how much handier a pencil thin barrel was than an HBAR, but Bushmaster had yet to release their superlight carbine.

Back then lots of people were getting HBARs turned down to M16A1 or M4 profiles. Now it's easier to order your rifle the way you want it from the factory.

[1911user]

What was the diameter of the A1 barrels?

I fired a few shots through an AR-15 with an A1 barrel a decade ago and it felt like a nice, handy carbine. Recently, I picked up an HBAR A2 configured AR-15 and was amazed at how heavy it felt; my FAL or Garand wasn't that much heavier.

I'm thinking about putting together an AR-15 for local 3-gun shooting, plinking, and for my kids to start learning with in a year or so. So far, the only parameters are lower cost hence iron sights, 6-position CAR stock, 20 inch barrel with 1/8-1/9 twist, a good flash suppressor, no loud muzzle brake, light overall weight preferably under 7.5 pounds, and home assembly.

The only option I've seen for the barrel is having one turned down. A chrome-lined barrel and chamber would be nice. Is anyone going to be making the slimmer profile 20 inch barrels anytime soon? I've read on a ar15.com some recently and it seems like there is a demand for lighter weight AR barrels 18-20 inches long.

[dadman]

http://groups.msn.com/TheMarylandAR15Shoot...e/techdata.msnw

[1911user]

http://groups.msn.com/TheMarylandAR15Shoot...e/techdata.msnw

good AR-15 link. thanks

[WJL]

FWIW:

In search of the optimum barrel, I started with a 20", 1:8 Wilson air-gauged stainless bull barrel (.920 it's entire length) that I had cut to 18" and turned down to .750. I found the weight and the length to be about perfect with the full-length gas system. Upon return, the gun wouldn't shoot better than 2.0 MOA under good conditions. I returned the barrel and had it cryo-ed.

Now with 75 and 77gr Black Hills ammo I can achieve better than 1 MOA.

My guess (and that of the competent gunsmith who did the work) is stress had been introduced into the barrel as it was turned down. The cryo process relieved the stress.

Either way, I ended up with a pretty good set-up. The gun now really shoots and I like the 1:8 twist with the bullets I shoot.