SS109

SS109 is a designation that can refer to several different things, most commonly a specific type of ammunition and a celestial object.

In the context of firearms, SS109 refers to a 5.56x45mm NATO cartridge. This round was developed in Belgium by FN Herstal and is characterized by its 62-grain projectile, which typically features a steel penetrator at the core, encased in a gilding metal jacket. The SS109 round was designed to be an improvement over the earlier M193 cartridge, offering better ballistic performance and penetration capabilities, particularly against light body armor and cover. It was adopted by the U.S. military as the M855 ball cartridge and has been widely used by NATO forces and other countries. The designation SS109 is also used for the rifle that fires this ammunition, the FN FNC.

Alternatively, SS109 can also refer to Messier 109, also known as NGC 3992. This is a barred spiral galaxy located in the constellation Ursa Major. It is situated approximately 85 million light-years away from Earth. Messier 109 is a member of the M109 Group, a galaxy group containing at least 15 galaxies. It was discovered by Pierre Méchain in 1781 and later cataloged by Charles Messier. The galaxy exhibits a prominent central bar and spiral arms, typical of its classification. Astronomers study Messier 109 to understand galactic structure, evolution, and the dynamics of galaxy groups.