No, because 7.62x39mm bullets are commonly up to .311 inches in diameter.
Please contact the Phase 5 customer service department regarding your specific issue. The thread pitch for the FATman Hex Brake is 1/2x28TPI, so it should work with that barrel.
The section that overlays the barrel (overlays a barrel 1.15") has an inside diameter of 0.950".
Yes, this should work with that rail. The rail information lists the inside diameter at 1.35" and the largest diameter of the brake (from point to point of the hex shape) is 1.260"
The correct model Phase 5 Weapon Systems Inc Fatman HexBrake for your 300 Blackout rifle would be MPN:FATMAN-5/8-24.
The outside diameter of the brake, from point to point of the hex shape, is 1.260 inches.
Yes, the correct model Phase 5 Weapon Systems Inc Fatman HexBrake for your Matador MAT-9 is model MPN:FATman-1/2-28 9mm.
The 5.56 Phase 5 Weapon Systems Inc Fatman HexBrake is threaded 1/2x28. The 7.62/.308 brake is 5/8x24. The MPN:FATMAN-9mm brake for 9mm, 7.62x39, and 6.8mm is threaded 1/2x36, and the MPN:FATman-1/2-28 9mm brake for 9mm, 7.62x39, and 6.8mm is threaded 1/2x28.
The Phase 5 Weapon Systems Inc Fatman HexBrake is made from steel and features a Mil-Spec Black Parkerized finish.
The Phase 5 Weapon Systems Inc Fatman HexBrakes once installed will cover about 1.65" of the barrel.