The Winchester Model 37 Steelbilt is a classic single-shot, break-action shotgun produced by Winchester from 1936-1963. More than 1 million were made. Action: Single-shot, break-open Capacity: 1 round Gauges: 12, 16, 20, 28, and .410 Barrel: Commonly 26-32" Choke: Often Full; other chokes were available Stock: Wood Steelbilt: Refers to Winchester's steel construction Hammer: External/semi-hammerless design Serial number: Original Model 37s generally were not serial numbered. Production: 1936-1963