Rock Island Arsenal Museum, the U.S. Army’s second oldest museum, opened to the public as the Ordnance Museum at Rock Island Arsenal in 1905. This original purpose resulted in a large and impressive small arms collection. The collection includes serial number 1 of the Model 1903 rifle, serial number 2 of the M1 Garand rifle, four weapons proven to be used by the Sioux or Cheyenne at the Battle of Little Bighorn, two Rappahannock Forge wall guns, and serial number G01 of the General Officers M15 pistol. Today the museum is dedicated to telling the story of Arsenal Island and its “People, Processes, and Products,” from the founding of Fort Armstrong in 1816 to current production on the island. Rock Island Arsenal is an active military installation, and all visitors must undergo a background check and be issued a pass to enter the island.