The most famous Colt products include the Colt Walker, made 1847 in the facilities of Eli Whitney Jr., the Single Action Army or Peacemaker, the Colt Python, and the Colt M1911 pistol, which is currently the longest-standing military and law enforcement service handgun in the world and is still used today. Though they did not develop it, for a long time Colt was also primarily responsible for all AR-15 and M16 rifle production, as well as many derivatives of those firearms. The most successful and famous of these are numerous M16 carbines, including the Colt Commando family, and the M4 carbine.