What does a newbie need for a barrel swap? I saw a few posts saying I can forget the torque wrench... What other tools will I need. Is there an online "tutorial" avaliable? Thanks.

Forget the torque wrench -

For a basic barrel swap, you can get away with a big sturdy bench vise, an [url=http://www.bushmaster.com/shopping/gunsmith/om-003.asp]action block[/url], and a [url=http://www.bushmaster.com/shopping/gunsmith/223-wrench.asp]combo barrel wrench[/url].

A hammer, set of punches, and pliers are also handy.  The [url=http://www.bushmaster.com/shopping/gunsmith/mbc-01.asp]gas tube wrench[/url] works really well, but if you're only doing a couple of barrel jobs, it's cheaper to merely crush a stuck gas tube with Vise-Grips and tap it out with a hammer, and then replace it with a new one.  A set of jeweler's files is handy to "adjust" the barrel pin slot in the upper to get the front sight base straight up.

WTF [?] [rolleyes]

Something you don't understand?

Yeah, what are you smoking?
WECSOG grad, yes?

Actually, this is me in my normal state.  Frightening, huh?  [:D]



Why, yes!!  How could you tell?  [:P]

[img]http://www.mindspring.com/~kmeans/ARFcom/wecsog.jpg[/img]

LOL!

[beer]

Hope you don't mind if I use your Picture...

Can I hijack my post back and get to the subject matter, please?

Go ahead!  The Coyote and background came from somewhere else with the word "GENIUS" on the business card.  I just added the lettering and FAL graphic.  Gotta love Photoshop! [:D]




Ok - WECSOG Barrel Mounting.

First, make sure your barrel is straight, and the front sight lines up with the rear.  I do it by eyeball.  You can also tie a piece of thread through the rear aperture to the front sight post.

If slants to one side, take a jeweler's file and with very light strokes, open up the barrel pin notch in the upper receiver.  When you get the front sight where you want it, take a hammer & punch and very lightly peen down the loose side of the notch with the barrel in place.  There should be no wobble.  Remember - light taps!!!  It doesn't take much.

(Most people skip this step, then they post a message here complaining that their rear sight had to be cranked all the way over to one side to zero it in.  Then they have to pull the barrel and re-do it.  Save yourself the trouble and do it right the first time.)

To mount the barrel, start turning the barrel nut until it stops (hand tight or thereabouts), then lean on the combo wrench until the next gas tube notch lines up.  Now STOP because you're done!!

One last tip = take an old gas tube and cut it down to about 2 or 3 inches.  Use that as an alignment pin in your bolt carrier key to line up the circlip, weld spring, delta ring, and finally the barrel nut as you're tightening it.

That's it!  Easy, huh?

topic thread [url=ar15.com/forums/topic.html?b=3&f=4&t=152822]#152822[/url]

And for even more confusion on barrel torque, read [url=http://www.ar15.com/forums/topic.html?b=3&f=4&t=161133]this thread[/url].

Basically you have two factions in this board -

One believes that you should follow the instructions in the TM to the letter, tightening and loosening several times, then tightening to the proscribed torque spec.  The other thinks you only need to tighten the barrel nut by feel until the next notch lines up.

Please hurry up and declare your loyalities so the other side can immediately start flaming you for making the wrong choice.  [:P]

Homo:

You are doing your "shadetree" thing again.  

Don't tell people to file the upper receiver index pin slot to achieve front sight alignment.  The slot is where it is in the upper for a reason.  The relationship of the extension pin and the receiver slot is important to keep the bolt lugs aligned properly with the lugs of the extension when the bolt closes.  Messing with this relationship will only cause the bolt to bind (or not engage at all) with the extension lugs as the bolt passes through the extension.

If the front sight is slanted off to one side then find out what the real problem is.

NEVER elongate the index slot in the upper receiver.

"Please hurry up and declare your loyalities so the other side can immediately start flaming you for making the wrong choice."

-How bout I study the "right" way, the "non-technical" way, and find my own way of doing it :) Then both sides can flame away.

That's "Mr. Erectus" to you!!  [:P]



Unfortunately, Russ, you have no direct experience with what you're talking about and am basing your statements on conjecture and a misunderstanding about the AR-15's operation.  On the other hand, I've used this technique on literally dozens of upper receivers (I've mounted ~130 AR barrels and have to do this around 2/3rds of the time) and have never once encountered this mysterious "bolt binding" you're so afraid of.

There's a couple of reasons for this:

1. We're talking about a tiny amount of material, and maybe just a few degrees of barrel rotation at the most.

2. The problem is almost always a misaligned or sloppy cut in the upper receiver.  In the original position, the barrel is cocked and I'm actually straightening it, improving "bolt lug alignment" not making it worse.

3. Even if the problem is a slight misalignment of the front sight base, there is more than enough tolerance in the locking lugs to rotate the barrel a degree or two to straighten it up.  And if the front sight base is so far off the it will cause this mysterious "bolt bind," the the barrel is crap and shouldn't be used anyway.



We're talking very tiny amounts of fitting required as a result of normal manufacturing tolerances.  This is common when it comes to guns.  Mixing and matching parts from various manufacturers (with varying quality!) only adds to the equation.  But except for the grossly canted front sight base on a defective barrel, this method works extremely well and keeps you from having to crank your windage all the way over to one side to get your new gun to sight in correctly.



And never comment on technical issues you have no direct experience with.

Your pal, Rex


[Edited to ficks speling misteaks.]

Not that I claim to have installed or replaced 130 AR barrels, but I know military guys who have done many mnay more.  They have never had to shave the post.  While I would agree there shouldn't be any problems in doing in that way, I have to wonder on why you have done it to so many.

What brands are you needing to do this to so often?

All brands.  There doesn't seem to be any rhyme or reason.  Recently I mounted an Olympic barrel in a no-name gun show A2 upper and it was perfect.  Last week I installed a Colt A2 barrel on a Colt flat-top upper and it slanted noticeably over to the left.  A little filing and peening on the notch fixed that.

Maybe I'm just too picky, but having to crank the windage knob 20 or 30 clicks over to the side just to zero a rifle doesn't seem right to me.  I know the customer who paid me to mount his barrel wouldn't have been happy sighting down his gun with a cock-eyed front sight.

With a cockeyed front site, isn't it more than likely that the front sight/gas block is the part that's cockeyed on the barrel. Perhaps when it was installed, it was misaligned by a coyote hair....wouldn't leaving the index pin alone and checking your front sight alignment on the barrel be more constructive?

That's the beauty of having so many folks to listen to here -- with a bit of lurking and patience one quickly learns who's advice to, uh, take with a grain of salt...

Uh, no.  You've obviously never tried to replace a front sight base before.

The front sight base is pressed onto the barrel, then the pin holes are drilled and the pins driven into place with a lot of force.  And if you were to remove the pins, rotate the front sight base slightly, redrill the barrel, and reinstall the pins, it would probably be loose.

Compare that to filing a tiny bit of material from a small slot.

These misalignments are very small - maybe a degree or two at the most.  Maybe less.  But definitely noticeable when sighting in your rifle and adjusting iron sights that move a tiny fraction of a degree with every click.  10 or 20 (or even more!) clicks makes a big difference.  And a few strokes with a file is all that it takes to fix it.

The problem is people read stuff here and think they know what they're doing, even though they've never tried to do it themselves.  Then others read their garbage and think it's the way to go.  Like the previous "Head Space" thread where the first answer to a simple question told you to remove the barrel extension, grind it down, reinstall it one turn farther, and ream the chamber.  What the hell was that??!?!?!  I guarantee that poster has never, EVER, in his entire life performed that operation.  EVER!!!  But when a newbie asks a simple question about having the correct headspace, that's the first thing that came out of their mouth.  Where do people get these horrendously stupid ideas?

Actually I know - it's right here.

So, people - just because you read it in a magazine article or saw someone post it here, don't quote technical instructions like they were the gospel unless you have actually done it yourself, and done it several times sucessfully.  When casting your pearls of wisdom, please feel free to state exactly how many times you've actually done what you're telling other people to do.  Only then does anything you have to say matter to the rest of us.

Not myself but I have had it done to compensate for throat erosion problems on a good shooting, expensive barrel.  Others I know have had it done to switch from shooting standard ojive bullets to VLD bullets.  I presented the example more as means to show how difficult it is if someone was hell bent on doing it to correct head space, not as a recommendation to this fellow.

And that's my point -

First, sending it out to have it done by someone else is not "Build It Yourself."

But more importantly, the poster was looking for elementary, basic information on building his very first AR.  And the first response talked about removing and reindexing barrel extensions.  The inexperienced builder may think that's what you really have to do when building an AR, when, in fact, that subject is extremely advanced and so far out of the scope of anything anyone on this board has done.  And the poor newbie gets led astray from the very start.  I think this is a disservice to inexperienced builders here who are merely looking for practical, real-world directions that will actually be helpful to them.

Plus, when things like that are posted, 187 other self-proclaimed know-it-alls will accept it as gospel and start repeating it in endless discussions over and over again even though they have absolutely no idea what their talking about, and that seriously dilutes any useful information a newbie hoped of gleaning but is now lost in all the noise and nonsensical chatter, and they're probably worse off than they were before.

Let me give you an analogy - on the very first day of 8th-grade Sex Education class, do you start the lecture by bringing up subjects like Auto-Erotic Asphyxiation and Fun With Gerbils?  Well, both those subjects are about sex, but that's not where you want a newbie's starting point to be, and it's not going to help them during they're very first encounter.  At least I hope not.  [:P]

This is why when someone asks a question, I feel you should only reply on subjects that you have had extensive personal experience with, and should limit responses to info that directly addresses the problem at hand.  Otherwise I think that replies actually do more harm than good.

Even after reading everything here (and elsewhere) on this subject, I personally would not attempt this unless I had someone experienced to walk me through it & watch over my shoulder the first time.  But I have two left hands with five thumbs each - you may not be so unfortunate.  FWIW, I always buy complete uppers instead of trying to change barrels - pin out, pin in - even I can do it...

[LOLabove][ROFL2]

I have to say I am in 110% agreement with Homo Erectus on this.

There is not a thing wrong with his suggestion for filing and peening the slot for sight alignment, and in fact, the expediant, smart way to get the front sight straight.

Working on AR15's ain't rocket surgery!  Heck, they let 17 and 18 yr old kids work on them in the military, so it can't be that hard.  Don't make more of a simple operation that it really is.