I have 2 X-Caliber (their #3 contour - barrel ends with approx a .900 inch diameter) both are 1-7 twist 6 groove. 1 finished at 22" and both have muzzle already threaded 5/8-24", The second finishes at 24". I have one with a thread protector the other with X-Caliber branded Terminator Muzzle Brake. Whom ever buys the first gets the choice thread protector or brake. Barrel with thread protector 500$ shipped, barrel with muzzle brake 550$ shipped. If you buy both I'll ship both for 1000$