It looks like I will be putting an M4gery together for a farsighted individual. The intended use is SHTF scenarios, including possible use as a primary or secondary HD gun. What sighting systems work best for farsighted folks? Give me your ideas. I will vet them, and present them to the individual. I still have good vision, so this is new to me. I will keep an open mind. Assume the individual will not be using corrective glasses when shooting.