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Old December 23, 1999, 03:39 PM   #1
zardoz
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Join Date: December 23, 1999
Location: Burlington, CT, USA
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Just found this site today; looks great!
Help. . . . .
I need to convert pre-ban AR upper to post-ban. I know I must cut off the bayonet lug and remove flash suppressor. My question is
how can I, with a modest workshop, at home,
"permanently" attach a muzzle brake on existing threads on the barrel end?
I heard of blind pinning and silver soldering from AR-15.com but these don't sound practical for a home "smith".
Any suggestions? can I use a low temp solder so as to not have to refinish barrel(450 degree melting)?
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Old December 23, 1999, 07:37 PM   #2
Joe Blacke
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Because your preban barrel will be threaded, you must either blind pin and weld, or completely weld the brake to the barrel (four equidistant points or circumferance weld).

The BATF has stated that you must use high temp silver solder if you intend to solder the brake to the barrel.

This topic is covered exensivly on AR15.com, as you stated, but unfortunately it is the only way.

However, you can send your barrel, or barreled upper to manufacturers like Busmaster or Smith Enterprise who will do the work for you for a small fee. In fact Wilson Combat has just announced a muzzle brake that looks a lot like the A2 flash hider, but is BATF approved. I believe that they will install their brake for about $75 (including the cost of the brake and labor).
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Old December 23, 1999, 09:55 PM   #3
DeBee
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Welcome to the Firing Line!

The simple answer is no. There is no easy way to convert pre to post short of cutting the barrel and recrowning (and even that's not easy if you want to do it right...) Low temp solder won't pass BATF inspection. Silver solder will, but that barrel will soak up alot of heat making the job very difficult and blind pinning ain't no walk in the park either... Real easy to make a big mess of it. Here is my plan:

I am currently looking for a Colt A2 Upper Lightweight with 16" 1x9 twist chrome lined barrel. As far as I can tell, these are not available in post ban configuration...

So, I am going to order a preban upper and immediately send it off to Wilson's Combat Handguns, who, just recently, began to produce a 100% BATF legal AR muzzle brake that looks very much like the A2 birdcage. They manufacture it with a slightly increased diameter so you cannot launch rifle launched grenades ( and we all know how easily it is to get rifle launched grenades... $1.78 at Walmart for 25 right???).

$80 bucks installed and if it is anything like the other goodies they produce, it will be top notch and well worth the money...

Then, I'll get out the dremel motor tool (oh no) and grind off the "hooks" that hold the bayonet on the lug. That way I won't have the castrated look of a cut off lug. Touch up with primer and paint. I'm told this will pass BATF inspection.

[This message has been edited by DeBee (edited December 23, 1999).]
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Old December 28, 1999, 12:11 AM   #4
TOPKICK
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Join Date: October 10, 1999
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I'm lost here. Why would you want to convert from pre to post? Do we have to due to some law, etc? I'm serious! I own a pre-ban AR-15 with bayonet lug, etc. It is the "Shorty" version and I was trying to figure a way to make my bayonet work with the lug being so far back. But now????????????? Help!

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Old December 28, 1999, 08:58 AM   #5
George Stringer
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Topkick, as far as I know, nothing has changed. George
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Old December 28, 1999, 09:15 AM   #6
zardoz
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I have a pre-ban upper as my post indicated,
I don't have a pre-ban lower to put it on;
therefore it is illegal to use it on my post-ban lower. I don't want to convert the upper, I have to.
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Old December 28, 1999, 10:49 AM   #7
Kernel
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zardoz, There's nothing in the law that says you can't have a threaded muzzle on a post-ban. You just can't put a muzzle brake on a threaded muzzle unless it's permanently attached. The way I see it you got four options: 1) take the flash suppressor off and leave the bare threads as-is (looks ugly), 2) screw on a plain thread-cap or a non-brake/non-flash suppressor look-a-like-thingy (there are companies that sell'em), 3) cut the threads off & recrown (best to have a smith do that), or 4) get a BATF approved brake and permanently attach it (blind pinning is not difficult, even for a novice). Those are your choices. Bottom line: it IS legal to leave the threads on if you want. The bayonet lug has gotta go if you want to put it on a post-ban lower. -- Kernel
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Old December 28, 1999, 02:53 PM   #8
TOPKICK
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Thanks guys. I understand now.(while slapping forehead with palm of hand) Now if I could just get that bayonet to fit right!!!!

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Old December 30, 1999, 11:11 AM   #9
Joe Blacke
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A threaded barrel is NOT okay for a postban.
If your barrel is threaded, a muzzle brake or barrel cap must be permanently attached or the threads removed.

The 1994 crime bill states that the AR15 pattern rifles are considered assault rifles if they have more than two "evil" features. Since they already accept a detachable magazine and have a pistol grip, they can't have a flash hider, bayonet lug, collapsible stock, or grenade launcher.

Topkick,

If your rifle was assembled before 9/13/94, and has a 16" barrel with a flashider, your will have difficulty mounting a bayonet because your rifle is not milspec. You will need to purchase an adapter (I believe Bushmaster sells these). The reason that the military M-4 has a 14.5" barrel is so that a bayonet will fit without modification.
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Old December 31, 1999, 08:30 AM   #10
artech
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Maybe I can clear some of this up here. There is nothing SPECIFICALLY stating that threads are illegal on a postban AR, but if you carefully read the stupid law, it is the only legal option left at the end. That or a brake permanently covering those threads, or a complete redesign of the rifle.

To the best of my knowledge, ATF still requires blind pinning with the pins welded over or straight welding to be considered permanently attached. This was still the case earlier this year. Solder is not going to do the trick.

Modifying a barrel at home is not easy, but if you are careful, it can be done. Cutting off the bayonet lug can be done with a hacksaw and filed smooth, then cold-blued, that's pretty easy. The muzzle is a different story.

If the barrel is chrome lined, I do not advise cutting it down, as this damages the chrome lining and will eventually cause the chrome to erode away from the muzzle, causing accuracy problems. In this case, getting a brake and taking it to a machine shop or gunsmith to have it installed is probably your best course of action.

If it is not lined, cutting it down(unless it is a 16 inch barrel) would be simplest, a 10 minute job on a lathe, again at a gunsmith. Or you can do it yourself, but if you do you must use EXTREME caution when working on it not to damage the inside of the bore, as the rifle will be inaccurate and that's no fun.

The 16 inch barrels were actually issued and MILSPEC at one time, though they aren't any longer. There really isn't much you can do with a bayonet on a carbine anyway, so it's kind of a moot point.

If someone is bound and determined to mount one, probably modifying a Garand bayonet(much longer)to fit a carbine would be easier than making an adapter, the ones Bushmaster sells are actually for the old model rifles they used to build, and they won't fit an AR's heavy barrel.

Hope this helps.

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