Any petroleum based solvent mixture will not remove chlorate salts. Use hot soapy water, and rinse with hot water followed by oiling the cleaned barrel.
To test your primers to see if they leave rust producing salts: Take a 3" putty knife, remove all oil and or grease, polish the blade to a bright shine with fine abrasive paper, fire a primed cartridge into the blade from about one to 3 inches, place the blade overnight in a humid atmosphere (a wet rag at the bottom of a seal able container {ie. tupperware} over night. The next day the blade will show a close shotgun like pattern of rust where the priming compound hit it. The rest of the blade may show some rusting, but if the primer is the cause it will be very apparent.
Good luck , Brodie