These are old 12 gauge brass shotgun shell casings from Italy.
Sold at Auction: 20 VINTAGE WINCHESTER 12GAUGE BRASS SHOTGUN CASING
Vintage French bronze knife rests in the shape of shotgun shells
Shotgun shell - Wikipedia
Pair of 1900 Winchester No 12 Brass Shot Gun
Winchester Shotshell Headstamps
Item Gone: FS Alcan Solid Brass Italy 12 gauge Shells 70 NEW OLD STOCK IN BOX
Shotgun shell - Wikipedia
MAGTECH AMMUNITION SHOTSHELL BRASS
An old Winchester brass and loaded copper shot shell case are both 12 gauge. - Antique Mystique
Sold at Auction: Box of (68) 10 Ga. Brass Shotgun Shells. WRA Co. Rival, Hart's, UMC Club.
Lizzy J's Handmade Round Gold Plated 12 Gauge Shotgun Bullet Shell Cuff Bracelet – En Reverie