Sight systems comprise a sight receiver and a base attachable to and detachable from a sight receiver. A base carries a sighting component, such as an iron sight or optic sight. A sighting component may be attachably and detachably mounted to a base, or a sighting component may be made integrally with a base. A base may carry plural sighting components. Sight systems may include plural interchangeable sight receivers, bases, and/or sighting components.
In some embodiments, interfitting structures at least partially restrain or retain a base and a sight receiver in longitudinal and lateral alignment, with such structures being longitudinally oriented. In some embodiments, interfitting structures at least partially restrain or retain a base and a sighting component in longitudinal alignment and lateral alignment, with such structures being longitudinally oriented. Some embodiments provide a fastener operable with a compatible and/or complementary surface, together used to urge interfitting parts together tightly.