The early Mdl. 1917 revolvers were bored with open chambers. They could not be fired without the Half Moon clips. These guns following WWI were issued to rural postman during the 1920-1930s when the era of the Automobile Bandits were a great danger. These handguns sold for $12.00 to $18.00 dollars in the late 1950s. If you had a friend in the National Guard .45 ACP ammo was free. The Peters Ctg. Company introduced the .45 AR for civilians. No clips were needed for the AR. Many handgunners learned to use big bore handguns because of these old War Horses. Thanks for the interesting post on an American classic.