I've looked around and this information is eluding me.
Can anyone point me in the directon where I can find the specs for fitting one on a barrel?
What I'm looking for is, thread size, and length of threads, the stupid stuff

[url=ar15.com/forums/topic.html?b=3&f=4&t=161981]barrel extension install?[/url]

Thanks for the link notack. I know how it goes together, I'm looking for the actual specifications. Thread pitch, amount of threads and so on. Thanks anyways!!!

NRA article, "REPRINT"... I have it as a small loose booklet. Article titled-- "Heavy Match Barrel Enhances AR-15 Accuracy"

Thread pitch is .8125"-16, .620" +/- .001" from face to shoulder face, and a releif of .100" from the shoulder back towards the barrel face (like what you see with flash hider threads).

Turn extension on and off several times, till full contact seen, torque 150 ft-lb, Finish headspace chambering barrel, and install the index pin.