These are loaded antique Winchester brass shotgun shells in 12

Black Powder Shot Shells

Pair of 1900 Winchester No 12 Brass Shot Gun

Winchester 12 Gauge Light Target Loads - AA127

12 Gauge Brass Shotgun Hulls for 2 1/2 Chambers Box of 25

WInchester's 1911 Was the Most Dangerous Shotgun Ever

The Classics: Winchester Model 1897 Trench Gun

Winchester AA Low Recoil/Low Noise Target Loads Shotshells

Winchester 12 Gauge - MODEL 1897, ALL ORIGINAL TRENCH GUN, BRASS SHELLS, BAYONET, BOOK, vintage firearms inc

An old Winchester brass and loaded copper shot shell case are both 12 gauge. - Antique Mystique

8 Gauge Shotgun: Why It Went Extinct