Ar platform rifles after every 250 rounds or less if using a can, bolt guns twice a year if they have been properly broke in ,
1. Never ever clean your rifle from the muzzle always clean from the chamber.. cleaning from the muzzle is a good way to ruin a crown.
2. get all the copper out and keep it out, it is hard to do if you do not properly break in a new barrel but once done it is a dream to clean and accurate as hell....