Auto is a colloquial term used to refer to an autoloader, or a gun with an automatic action, or Automatic ammunition.

ammunition

See ACP

gun

autoloader

See action, semiautomatic

automatic action

See action, automatic

 

Footnotes / Sources:

“Glossary ⇒.” Sporting Arms and Ammunition Manufacturers’ Institute. Ed. SAAMI’s Technical Committee. Web. 15-18 Jan. 2011.

 

Question:

• Do you know of any other gun related uses of the term auto?