The Model 1900 was very similar to the model 1895, but with only a few components finished in O.D. green. The U.S. Army purchased several M1900s. All Gatling Models 1895–1903 could be mounted on an armored field carriage. In 1903, the Army converted its M1900 guns into .30 Army to fit the new .30-03 cartridge (standardized for the M1903 Springfield rifle) as the M1903. The later M1903-'06 was an M1903 converted to .30-06. This conversion was principally carried out at the Army's Springfield Armory arsenal repair shops. All models of Gatling guns were declared obsolete by the U.S. military in 1911, after 45 years of service.