Warning

 

Close
Confirm Action

Are you sure you wish to do this?

Cancel Confirm
AR15.COM
AR Sponsor
5/20/2004 2:12:52 PM EDT
I'm replacing my 20" barrel with an M4 barrel. I have the barrel wrench and vice blocks. Are there any headspace or timing issues to consider when installing a barrel or is it just straight forward "screw off the old one and screw on the new one"?
5/20/2004 6:32:15 PM EDT
[#1]
pretty straight forward -

remove gas tube
remove barrel nut

if you want to check the headspacing of your new barrel, get a set of gauges (bushmaster sells them).
reassemble your upper - and then test with guage and your current bolt.

5/21/2004 3:46:21 AM EDT
[#2]
At the top of this forum TACKED especially for s is the info you seek: www.ar15.com/forums/topic.html?b=3&f=4&t=184086

That's why their TACKED, up TOP.

Mike
5/21/2004 7:01:22 PM EDT
[#3]

Quoted:
pretty straight forward -

remove gas tube
remove barrel nut

if you want to check the headspacing of your new barrel, get a set of gauges (bushmaster sells them).
reassemble your upper - and then test with guage and your current bolt.


While BravoCompanyUSA is 100% correct, it is also correct to add that you don't need to check headspace (unless you've put many 1,000's of rounds through the old barrel+bolt.)
5/23/2004 8:55:15 AM EDT
[#4]
I haven't been called a newbie since I was a Lance Corporal....hug.gif........14 years ago!!! Thanks for the info!!
5/23/2004 8:59:17 AM EDT
[#5]
Thanks for the info. Although I've had the rifle for many years, it hasn't had that many rounds put through it, so the headspace should be OK.
5/23/2004 6:19:41 PM EDT
[#6]

Quoted:
I'm replacing my 20" barrel with an M4 barrel. I have the barrel wrench and vice blocks. Are there any headspace or timing issues to consider when installing a barrel or is it just straight forward "screw off the old one and screw on the new one"?




Once you do it the first time you'll see it's actually pretty easy and nothing to get worried about.  A couple of tips -

Don't worry about headspace.  You can't change it anyway.

Forget the vise blocks and get an action block, otherwise you could damage the slot in the upper receiver.

The one step most people don't do is aligning the front sight straight up.  That's why most home-built ARs have a canted front sight and the rear sight windage knob cranked way over to one side.  You do it by "adjusting" the barrel pin slot in the upper receiver with a file, then tightening the slot up with a punch so the barrel won't move when spin the barrel nut.

Get all the details by reading this thread.
5/24/2004 3:59:48 PM EDT
[#7]
HE, thanks for the info. One of the other members gave me a link to your barrel changing instructions earlier and I've already read it; it's an excellent guide. I have an action block, not the barrel vice blocks and I'm an experienced maintenance mechanic, so with your instructions it should be a piece of cake! Again, they're excellent instructions and I really appreciate the advice. One more thing....My rifle is a pre-ban A2 and I'm putting a 14.5 in. M4 barrel on it. What do I need to do about the flash hider? I can't use the A2 hider because it's too short, right?  I have a Phantom flash suppressor, but I understand it has to be "permanently attached", but I'm getting a lot of different answers to what that means exactly. Can I get by with just using something like permanent Loc-tite or JB Weld, or should I setscrew it and weld the head (or something similar)? I really don't want to weld it if I don't have to, (although I am quite proficient at TIG welding), but I also don't want to go to prison if some overzealous cop wants to inspect my rifle while at the range and finds it not kosher!! Thanks again for the info!!!
AR Sponsor