View Full Version : Changing an AR barrel

Jeff Thomas
September 4, 1999, 12:21 AM
Another 'how difficult is this' question.

How tough is it to change an AR barrel? Need a special tool, no?

Thanks. Regards from AZ

September 4, 1999, 12:45 AM
It is not that difficult. You will need an action block($40.00), vise, 1/2"torque wrench, 1/2" breaker bar, barrel wrench, moly d, headspace gauge, snap ring pliers and a marine corps tech manual. Read the manual first. HTH

4V50 Gary
September 4, 1999, 11:37 AM
In lieu of an action block, you can also use barrel blocks. One word of caution about them is that they may mar the finish. For one extra heavy barrel (1 1/8") that I installed on a Hi-rise Flat Top upper (which couldn't be put into an action block), a barrel block was made of hard wood drilled to the right diameter and then halved on a table saw.

Do get the manual and read it first. It's not hard and actually very fun. All the tools needed have been listed in the above posting.

Vigilantibus et non dormientibus jura subveniunt

September 4, 1999, 05:10 PM
The manual is available online at www.AR15.com (http://www.AR15.com,) they have it free for the download. Changing barrels is REALLY easy on AR's, it takes about 2 minutes after you get the hang of it. Good luck!

With my shield or on it...

[This message has been edited by artech (edited September 04, 1999).]

Ken Cook
September 13, 1999, 11:20 AM
A note here,
When I was an armorer in the Marine Corps,
the manual stated (and still does) to torque the barrel to 30 foot/pounds and then "tighten to align."
What they're talking about, is lining up the Star nut so that the gas tube will pass through it and into the upper receiver without binding.
The only problem with this is, occasionally, you have to tighten the barrel to 70 foot/pounds or more to get the star nut to line up!
Oddly, and for reasons that neither I nor the "best minds" at Marine Corps Logistics Base Albany Georgia couldn't figure out, was that this very often caused the rifle to shoot as much as 42 inches left at 200 yards!
It never affected right windage or elevation, but it would OFTEN send the round left of target.
The fix that I came up with, was to tighten the barrel to NO MORE THAN 45 foot/pounds and then if there is a point of the star nut in the way of the Upper Receiver Gas Tube Hole, very carefully dremel the offending point off of the nut.
Of course, this is an unauthorize modification in the Corps, but I've done it to several personal AR15s and it works like a charm.
No ill side effects noticed after thousands of rounds!
Hope it helps!

Your mind is your primary weapon.

Jeff Thomas
September 13, 1999, 11:51 PM
Thanks for all the help. There's nothing like experience, and I appreciate being able to benefit from yours. Take care.

Regards from AZ

September 14, 1999, 01:55 AM
Mr. Cook,

That is a great idea. Over on AR15.com you would not believe the # of people that ask this same question. Apparently bushmaster has this problem alot. No one knows what they do to fix it though. Your fix really makes sense.



September 14, 1999, 08:06 PM
If it weren't for the problems associated with people wanting to litigate rather than investigate I would tell you about the germanic method of "gutentigcht" It does require the use of a small hammer and a brass drift. Usually never a die grinder.
I wish that I could speak on this subject.