Learn more about the M4/M16-SeriesThe M4 and M16 are the most commonly used shoulder fired small arms in the United States military. The M16, originally used in the Vietnam War, has been constantly improved upon and upgraded over the years and is still in use today! The M4 Carbine, based on the M16 platform, was designed as a more compact and maneuverable alternative to the M16 assault rifle, with a more compact barrel and a retractable stock. One of the many improvements made to the M4 carbine and M16 assault rifle over the years was the addition of a rail interface system, which allows the operator to quickly and easily mount optics and accessories to the weapon making it more efficient. Airsoft Megastore carries one of the largest selections of M4 & M16 airsoft guns available on the market, and all for the guaranteed lowest price!