Barrel
 

How do you make your own barrel, I have access to a lathe. And know how to operate it and also a 16" INCH BARREL. Need specs for an m4 profile

Gunmakers and barrel makers use specialized tooling to bore the bore, and then rifle it. Takes more than standard machine tools. You will also need a barrel straightener after it is rifled. Stresses induced in rifling usually cause a wonky barrel that is cured by bending slightly.

Pratt & Whitney "owns it",as far as I'm concerned.......and its most assuredly one of those,"if you gotta ask" sort of things,WRT $$$.Further reading below.

http://www.border-barrels.com/articles/bmart.htm