Why would you want a male to male? Are you sure you're not thinking a 1/2-20 UNF female to 1/2-28 UNF male adapter? That way if you're barrel is threaded with 1/2-20 UNF, you can screw the female 1/2-20 UNF portion of the adapter over your threads, and the 1/2-28 UNF threaded portion will be exposed to accept a suppressor that is threaded with 1/2-28 UNF.
Why would you want a male to male? Are you sure you're not thinking a 1/2-20 UNF female to 1/2-28 UNF male adapter? That way if you're barrel is threaded with 1/2-20 UNF, you can screw the female 1/2-20 UNF portion of the adapter over your threads, and the 1/2-28 UNF threaded portion will be exposed to accept a suppressor that is threaded with 1/2-28 UNF.
FYI - the AA S500 has a FEMALE thread on the shroud, not male like most other brands. Gun with female and LDC with female requires an adapter with male/male.