This is an example of "causative have" in the command form (imperative tense). The text "Have your guns serviced regularly" assumes that most gun owners will have their guns serviced by someone else. Consider the following sentence. "See a dentist regularly and have your teeth cleaned." "See a dentist" is the command form of "you see a dentist" ("you go and see"). "Have your teeth cleaned" is the command form of the causative "you have your teeth cleaned (by the dentist)."

Hi Sergey, It can mean both, such as having your car serviced or having your house cleaned. The statement does not require a specific person to do it, the goal is to "have it done". However if you were to say, "I'd like to have my guns serviced" you are now saying you'd like somenone else to do it for you, this would be a request. The statement "Have your guns serviced regularly" is a reminder more so than a request. I hope this helps, this is my first time commenting on this app.