Hogleg

A plain-clothes man with his coat off and his hog's leg looking like a fire plug against his ribs took one eye off his evening paper […].

Well I been a-ridin' shotgun on the Houston-Dallas stage / I got me a sawed-off hogleg, twenty is the number gauge / I'd shoot anybody, that would try to stop this ride / A lot of outlaws tried it, a lot of outlaws died.