05 My light gun sometimes loses accuracy after a while

Assuming your calibration is done correctly, your gun should be accurate so long as your shooting position, distance or style did not change after calibration. If they have changed, you will need to recalibrate your gun. Put your gun in Calibration Mode at any time by pressing the H-Calibration button twice quickly. If you are in the middle of the game, first press the Start button to pause the game, then go into Calibration Mode and then press Start to resume play.