This Winchester manufactured 28" plain barrel with a fixed modified choke and very good bore is for the model 12 slide action shotgun in 16 gauge with a 2 3/4" chamber. The overall external condition is very good retaining 97% of an added hot immersion blue finish that looks slightly plum in color with some scattered faint specks of pin prick pitting under the finish.  (file photos)

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

16 Gauge: 1677926