Flame arrestors and methods of making flame arrestors are described herein. An example flame arrestor includes a cylindrical body. The body includes a first end and a second end opposite the first end. The first end of the body has an end surface. The body also includes a recess formed in the end surface of the first end. The recess is defined by a recessed surface extending inward from the end surface toward the second end. The body further includes a set of channels formed through the body between the first and second ends. The channels extend through the recessed surface.