Orbital semimajor axis of the moon (basically the orbit radius): 384400 km
Subtract earth’s radius: becomes 378000 km above earth’s surface at mean sea level.
Moon radius: 1737.4 km
tan-1(1737.4 / 378000) = 0.26 degrees
Conclusion: at best, assuming the moon is directly overhead and any glancing contact is a success, you can deviate maximally 0.26 degrees from a dead centre hit to hit the moon.
Counterpoint:
Orbital semimajor axis of the moon (basically the orbit radius): 384400 km
Subtract earth’s radius: becomes 378000 km above earth’s surface at mean sea level.
Moon radius: 1737.4 km
tan-1(1737.4 / 378000) = 0.26 degrees
Conclusion: at best, assuming the moon is directly overhead and any glancing contact is a success, you can deviate maximally 0.26 degrees from a dead centre hit to hit the moon.
Good luck with that.