AR15 Barrel replacement


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Zundfolge
June 29, 2006, 11:23 PM
How difficult is it to swap out barrels on an AR (not complete uppers, just the barrel)?

I've got a Bushmaster Carbine with a heavy barrel (and "post ban" non-bayonette lug gas block) that I'd like to change to an M4 style barrel. I'm thinking it would be less expensive to just buy a milspec M4 profile 16" barrel than to buy a whole upper.


I've seen plenty of barrels in the $150 range and a new upper would be at least twice that, however if I have to pay a gunsmith another $50-$75 to put it together or if I have to spend about the same on special tools, I might as well just spend a little more and get the flat top upper I'd rather have (my current upper is an A2).



Or maybe I'm looking at this all wrong, maybe I should just sell my A2 upper and buy an A3 ... what is a lightly used, excellent condition Bushmaster 16" A2 upper worth?

This is my upper. (http://www.bushmaster.com/shopping/uppers/post-ban/pura2b16.asp)

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Zak Smith
June 29, 2006, 11:30 PM
You need a receiver vice block set and a barrel nut wrench. There are directions on AR15.com regarding barrel removal and reinstallation.

mrmeval
June 29, 2006, 11:38 PM
http://www.thehighroad.org/showthread.php?t=4966

rbernie
June 29, 2006, 11:52 PM
Of all the receiver blocks, I prefer the DPMS (http://www.pantherarms.com/10Expand.asp?ProductCode=TL-PRC) version the best - works on all sorts of receivers, including the tactical or hi-rise versions. If you have a sturdy bench and vice, you can buy the receiver block and barrel nut wrench and do it yourself in about five minutes.

Most all barrels come with the barrel extension already installed, so they're headspaced and ready to go. All you have to do is assemble.

Zundfolge
June 30, 2006, 12:06 AM
Ah, so $50 or so for the vise block ... another $50 (at least) for a bench mounted vise so I might as well just look at getting a whole new upper (although I could find hundreds of other uses for a bench vise).

So any idea what my used upper is worth (assuming excellent condition)?

mc223
June 30, 2006, 04:29 AM
Is it the weight or the look of the H-bar carbine barrel that you want to change, or is there some other reason for the change?
You could probably work a trade for what you want.

I lived in and around Colorado Springs For 23 years. moved to Wis 6 years ago. Got tired of the traffic.

mrmeval
June 30, 2006, 06:43 AM
Need photos of the upper and a description. Most start at 300 and even used ones command a good price.

rbernie
June 30, 2006, 09:04 AM
Ah, so $50 or so for the vise block ... another $50 (at least) for a bench mounted vise But it's a one-time expense. I've build and rebuild and swapped around at least half a dozen uppers. It's MORE than paid for itself....

Zundfolge
June 30, 2006, 10:35 AM
The issue is 99% weight ... AR's are just nose heavy (and 1% "it looks cooler"...plus you never know, someday I might want to mount an M203 :D).

Maybe thats the question I should ask. Is the M4 profile barrel that much lighter than my heavy barrel?


In the first post I linked Bushmaster's page for the exact same model of upper I've got ... I don't have any photos of the upper by it self (I imagine I could dig up a photo or two of the entire rifle).

Vitamin G
June 30, 2006, 10:51 AM
You might be interested in a bushy superlight upper?
I like mine, but I think they look a little silly with an a2 brake.

rbernie
June 30, 2006, 12:11 PM
I built an upper with a 20" 1:8 fluted Shaw stainless barrel from Model1Sales. It's more rigid than a pencil barrel but not as heavy as an HBAR. There are better custom barrels, to be sure, but the Shaw is as good as any other non-custom barrel and is certainly good enough for my needs.

http://www.model1sales.com/images/bar20.gif

For $250, it was a steal... Of course, since I have the tools to build my own uppers, I can do this kind of customized mix-n-match building... ;)

444
June 30, 2006, 12:27 PM
If I was you, I would just buy a new upper.

You want a new barrel. You don't like the carry handle receiver. You don't own any of the tools needed to change out an barrel.
Just buy a new upper.


That being said, you can probably find someone with the stuff to change out your barrel pretty easily. AR15.com has a "Hometown" section of their board. You go to the section of the board dedicated to the state you live in. Ask on there and I bet you will find someone near you that is more than willing to help you out.

mrmeval
June 30, 2006, 08:34 PM
Get a light barrel and then balance it with this metal (http://cgi.ebay.com/Osmium-solid-metal-pieces-1g-to-1kg-element-sample_W0QQitemZ6206291701QQihZ010QQcategoryZ413QQssPageNameZWDVWQQrdZ1QQcmdZViewItem) in the buttstock.

Not only tacticool but the most dense substance on earth.

buttrap
July 1, 2006, 12:59 AM
You really dont need all the fancy tools to change a tube on a AR. Just the barrel nut wrench and a vice with 2 2x4s. I have done a few just standing on the receiver on the floor. They only torque at like 35 pounds or whats really near to what a valve cover on a engine torques at.

cracked butt
July 1, 2006, 09:43 AM
Not only tacticool but the most dense substance on earth.

[thread drift]...and one of the most toxic. I've never seen osmium for saleon the internet until now.:) [/thread drift]

mrmeval
July 1, 2006, 09:00 PM
U235 is a worse as a toxin. And at 35 dollars a gram it's not very much. It's a spec that's 1/24th of a cubic centimeter, a pound(453.5 gram) is $14058.50 and it's only 18.2 cubic centimeters. :what:

I really really want it as a barrel weight but I suppose the pound of tungsten will have to suffice. :neener:

cacop
July 1, 2006, 10:00 PM
At my Colt Armorer's school they didn't even teach us how to do it because it is so hard to do it right. Even the instructor said it isn't worth doing himself and he has all kinds of tools to do it right with. He said that Colt puts the barrel on first then puts on the gas block. If you do it the reverse you may never get it shooting straight without a lot of work. Basically when you change barrels you are doing it the hard way. Change uppers or send it back to the factory=easy way.

Personally I would buy a new upper.

pcf
July 1, 2006, 10:09 PM
At my Colt Armorer's school they didn't even teach us how to do it because it is so hard to do it right. Even the instructor said it isn't worth doing himself and he has all kinds of tools to do it right with. He said that Colt puts the barrel on first then puts on the gas block. If you do it the reverse you may never get it shooting straight without a lot of work. Basically when you change barrels you are doing it the hard way. Change uppers or send it back to the factory=easy way.

You got lied to. The hardest part of barrel replacement is getting the FSB straight, and that's not hard. As far as mechanical aptitude I'm hardly above critters that don't have opposable thumbs. I can change the barrel on an AR15.

If you can change the oil on a Honda, AR-15 barrels are a walk in the park.

another $50 (at least) for a bench mounted vise
Garage sale - $10 max

lycanthrope
July 1, 2006, 10:19 PM
I'd hate to have some nice uppers laying around with shot out barrels and no way to replace them........

Shoot enough and that will start to happen. The AR is very easy to work on and the support on ar15.com is huge.

DMK
July 1, 2006, 10:23 PM
Maybe thats the question I should ask. Is the M4 profile barrel that much lighter than my heavy barrel?If it were me, I'd go with either a Bushmaster Superlight or get an M4 Dissy and stretch your sight radius out. Bushy barrels are chome lined, made of good steel. Then add a good flash suppressor like a Vortex or Phantom.

Bushmaster's Barrel Weights:

Barrel Weight In Pounds ( for milled front sight subtract 0.2 pounds )

Barrel length_______Heavy Barrels______ Fluted Barrels

10"___________________2.0_________________1.9
11.5"________________ 2.2_________________2.0
14.5"________________ 2.5_________________2.2
16"___________________2.7_________________2.3
14.5"AK_______________2.7_________________2.4
14.5"MY_______________2.7_________________2.4
14.5"AM (phantom)_____2.7_________________2.4
11.5/5.5"____________ 2.6_________________2.5
16" Dissipator________3.0_________________2.6
20"___________________3.5_________________3.0
24"___________________3.9_________________3.1
26"___________________4.0_________________3.2

Military Style Barrels
16" Superlight________1.9
14.5"M4_______________2.0
14.5"M4AK____________ 2.2
14.5"M4MY____________ 2.2
14.5"M4AM (phantom)___2.2
16"M4_________________2.2
16"M4 Dissipator______2.3
20"A2(govt profile)___2.5

DMK
July 1, 2006, 10:34 PM
At my Colt Armorer's school they didn't even teach us how to do it because it is so hard to do it right. Even the instructor said it isn't worth doing himself and he has all kinds of tools to do it right with.
I'd be very dubious of that instructor's advice. Changing an AR barrel is incredibly easy. I did my first one in 15 minutes and it shot as straight as an arrow. It just needed a few clicks of windage at the range. I've done about six since then all with the same result. In fact, I took a few complete uppers apart just to Gunkote the barrels.

The only real issue is whether you to spend the money on the receiver block and barrel wrench or not. I like the freedom those tools give me.

He said that Colt puts the barrel on first then puts on the gas block.If Colt does that, they are doing it to save manufacturing costs somewhere. Any new barrel you buy will have the gas block installed and indexed properly. The only time you need to remove the gas block is to install a free float tube and then it's not difficult at all unless the pins don't want to come out.

Dave Rishar
July 1, 2006, 11:01 PM
One last thing to consider: when it's said that headspace isn't a concern because the barrel extension is installed at the factory, the implication is that you'll be using a barrel and bolt from the same source. (And that both were made correctly.) If they weren't, or they're from different sources...well, that warning in the operator's manual about not switching bolt assemblies isn't there to pad the page count.

Not saying that it will be an issue, as it almost never is. Just something to keep in mind, right? I can understand not wanting to pay someone to assemble one -- it really isn't difficult if you have the proper tools, or something close to them; however, you may want to pay someone to check the headspace (or even the entire assembly job) afterwards, just to be safe.

JNewell
July 2, 2006, 07:09 PM
I wonder if the post about it being too hard is referring to the front sight base. That is a job that isn't worth doing yourself. The pins are taper pins and the reliability of the rifle really depends on getting everything off and back on correctly. Changing the barrel is really not very hard if you have the tools and follow the book.

cacop
July 2, 2006, 10:24 PM
I think his issue was people starting to mess with their guns and not get it back together right. We have ARs at the office with the flash hiders off center. I know they didn't come from the factory like that.

He had a guy come in to his shop so bad on windage it was slammed to the side and it was still shooting off. It looks like it is an easy thing to do. He even admitted it. But is it really worth it when you can buy a new upper? If the barrel is toast I can understand because what have you got to loose?

The way I look at it why mess with something that works? Get a new upper and now you have two things that work. (Hopefully, he had a Bushy come from the factory with the barrel off bad. Must have been a Monday morning gun.)

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