This Winchester manufactured 24 3/4" shortened plain barrel with what was originally a fixed full choke but more open now and a very good bore is for the model 12 slide action shotgun in 20 gauge. The barrel exhibits a mixture of thinning original blue finish blending with an added cold blue finish over some spots of cleaned light pitting.  (file photos)

Note: Winchester model 12 slide action shotguns with the following gauges and serial numbers have been observed with this part:

20 Gauge: 22372, 37014 & 122475