AR barrel
Sir;
In threading your AR barrel with a die instead of a lathe be sure you start the threads square.
One way I did it was to mount the barrel in my three jaw chuck and use the tailstock to center the die in starting on the barrel - but when you do that, if you have a lathe go ahead and thread it anyway. Always thread to a shoulder and when you tighten it up do NOT use much pressure - you'll expand the barrel at the joint. Use "peel washers."
If its for a muzzle flash hider or brake use a "VORTEX" flash hider.
Harry B.