Coach gun A coach gun is a double - barrel shotgun , generally with barrels approximately 18 " in length placed side - by - side . The name comes from the use of such shotgun s on stagecoaches by shotgun messenger s in the American Wild West and during the Colonial period of Australia . Origins . The term " " Coach gun " " was coined in 1858 when Wells , Fargo & Co . began regular stagecoach service from Tipton , Missouri to San Francisco , California . They issued shotguns to its drivers and guards for defense along the perilous 2 , 800 mile route . The guard was called a shotgun messenger although the phrase riding shotgun was not coined until 1919 . There was no single manufacturer for the traditional coach gun , as it was a generic term describing a class of shotguns offered in a variety of barrel lengths from , either by the factory or from owners and gunsmiths cutting down the barrels . Early manufacturers . These shotguns featured external hammers and were manufactured by Remington Arms , Ithaca , Wm . Moore & Co . Meriden , Buckley , Burgess , Colt ' s Manufacturing Company , Hunter Arms , Husqvarna , Lefever , Parker , Sharps Rifle Manufacturing Company , Savage - Stevens , Villegia , and Westly Richards to name a few . Use in the Old West . Doc Holliday used a 10 gauge Wm . Moore & Co . coach gun to shoot Tom McLaury point - blank in the chest with buckshot during the Gunfight at the OK Corral in Tombstone , Arizona , on Wednesday , October 26 , 1881 . They stood in such close proximity that the town mortician was able to cover McLaury ' s wound with one hand . " Wyatt Earp also used both barrels of a 10 gauge coach gun to kill " Curly " Bill Brocius point - blank the next year . Brocius ' s body was nearly severed at the midsection . Modern makers . Modern coach guns are manufactured by Stoeger ( Brazil ) , Boito ( Brazil ) , Baikal ( Russia ) ( which is now being distributed by Remington under the name Spartan Gunworks ) , Huglu Armsco ( Turkey ) , Khan ( Turkey ) , Diamond ( Turkey ) , Rossi ( Brazil ) , and a variety of Chinese companies for US distribution through Century International Arms and Interstate Armscorp . Current usage . Modern coach guns are commonly encountered in Cowboy action shooting competitions , among collections of Western guns , as home - defense weapons , and even as " scrub guns " for hunting grouse , woodcock , rabbit , hare , and / or wild pig in scrub , bush or marshlands , where the 24 " + barrels of a traditional shotgun would prove unwieldy . The modern coach gun can be had in a variety of configurations suitable for both Cowboy Action Shooting competition and hunting . < br > Coach guns are similar to sawn - off shotgun s but differ in that coach guns manufactured after 1898 are offered as new with 18 " barrels and 26 " overall length , and meet legal requirements for civilian possession in the USA . Australia , and New Zealand have slightly different laws for length , with NZ requiring a minimum overall length of 30 " ( anything shorter is considered a pistol ) with no minimum barrel length and Australia requiring an 18 " barrel and a 30 " overall length . In the United Kingdom , however , shotguns must have a minimum barrel length of 24 " to be eligible for ownership on a Shotgun Certificate , and shotguns with barrels under this length ( which includes Coach guns ) must be obtained on the more stringent Firearms Certificate . Some modern coach guns feature internal hammers as opposed to the traditional external hammers .