huh?
You don't calibrate lightguns via mame, you calibrate them via using the "calibrate" switch setting on the side of the gun. It sounds to me like you are confused as to how you setup guns in mame. You make a ctrlr file and set the axis to "mousecode_0_x" or whatever for each axis. You can't set the axes within mame because lightguns don't "move" until you shoot, in which case the button would be binded to the axis anyway. If you are only using one lightgun, then I might suggest setting the new -multimouse flag to 0 which merges all mice axis and thus the games will already be mapped.