US Patent 9341426 Muzzle brake for firearm

A firearm muzzle brake may include a substantially cylindrical hollow first portion having a first end and a second end; a pair of opposed rows of slots extending through the first portion, each row extending axially along a side of the first portion; a pair of rows of ports extending through the first portion, each row extending axially along the first portion above one of the rows of slots; and a second portion having a first end received in the second end of the first portion, a second end, a central aperture extending through the second portion and being in fluid communication with the hollow first portion such that a bullet can pass through the first and second portions.