mare's leg
The Mare’s Leg (aka Mare’s Laig; both sometimes spelled without the apostrophe) was the name given to a customized shortened lever action rifle by Steve McQueen’s character on the American Western TV series Wanted: Dead or Alive.
"Mare's leg" is now a generic term for a Winchester Model 1892 (or modern derivative) with a shortened barrel and stock.
See also
This tag implicates lever_action (learn more).