I have a couple of Piercision Rifles brakes for sale. First one is a 5 port slabbed muscle brake that I had on a 300 Norma Imp for awhile. It's been tapered to blend into a Proof sendero contour barrel and is threaded 3/4-24. Second one is a new self timing 5 port muscle brake that is also threaded 3/4-24. $75 plus shipping for the tapered brake and $125 plus shipping for the self timing brake.