Someone wanna please explain to me this whole thing, and how its adjusted and such? Also what tools are needed to assemble an upper? Thanks!

Forget about headspacing - it's the one thing on an AR that you can't do anything about. Regardless what the Headspace Weenies on this board say, it's probably the least important factor to a home builder so don't worry about it.

If you want to know how to replace a barrel, go [url=http://www.ar15.com/forums/topic.html?b=3&f=4&t=173151]here[/url].

And bc of responses like that I get to "fix" (as in "correct") a couple of rifles a year.

Remember, insults are the result of incompetent arguement.

Info [url=http://ar15.com/forums/announcement.html?b=3&f=66&id=186]FAQ I[/url]

Will try to answer your question about 'headspace'. My understanding is that it is a dimension, usually measured in .0001's, between the face of the bolt and the face of a chambered gauge or test round. There are different acceptable and desirable amounts of headspace from caliber to caliber. Most bench rest chambers are cut so that there is very minimal headspace, to the point that if a burned grain of powder sticks to the bolt face, it will cause hard locking. This minimal headspace helps reduce case stretching. In a field gun, too tight head space might inhibit functioning. Same with an AR, there is usually a few thousands of headspace built into them, to allow for variances in ammunition. How to 'set' headspace on an AR ?  Install the barrel extension on an unchambered barrel (that is a whole project in itself, to get the extension aligned so that the gas port will fall in a barrel groove), and cut/ream the chamber till it will accept the gauge you have chosen, the bolt will rotate into locked position, with the chosen amount of clearance (headspace) between the bolt face and gauge..

I am curious as to how you 'fix' or 'correct' improper headspace. Would you please elaborate??

I seriously doubt that.  I've personally built over 130 rifles and have never encountered a headspace problem regardless of where I got the bolts and barrels.  The only common factor with all the ARs I've checked is they all tend to gauge at the long end of the spec.



I don't recall mentioning anyone by name, Roger.  But if you want to volunteer... [:P]

I really hate to see people like Pepsimayn, who hasn't even built an upper yet, get fixated on headspace when there's nothing he can do to change it (short of trying to find a equally but opposite out of spec bolt to match it).  Besides, a good factory M16 barrel will probably swallow the No-Go gauge, and maybe even the Field gauge and it's still good.  But the poor newbie is going to see this and freak out that his gun is unsafe.  It's not.

Too little headspace and the bolt won't close.  Too much and it's a little hard on the brass.  Big deal.  If you don't want to spend the money on a set of headspace gauges that you'll use once then throw in your drawer forever, just chamber a live round.  If the bolt closes, headspace isn't too short.  Pull the trigger, and if it fires, headspace isn't too long.  You're done.

See, I just saved you money on both a set of gauges [b]and[/b] a torque wrench!!  [:D]

Hey Pepsimayn,

I'll loan you a set of headspace gages. E-mail me. Just send them back to me when you're done with them.

Well thats mighty generous of you, but I don't have any of my components yet, and I'm not sure I have enough $$$ to even pull off the project, but Christmas IS coming...

Hmmmmmmm.  If being concerned about checking headspace is the [b]least[/b] important thing for a home-builder to worry about, I'm curious what the [b]most[/b] important thing is????

The [b]most[/b] important thing is to throw away your torque wrench.  [:P]

Heroin..... definately heroin....