I understand that full-size means "it's full sized", but I am not sure relative to what?
This is a full-size pistol.
Does "full-size" mean something is within the normal size range within a gun class when used for guns? For example, a shotgun that's the size of a full-size pistol would be called a compact shotgun. Is this the case or not? I am asking, because looking up a dictionary doesn't really help to get the meaning right.