Winchester Handgun Brass .357 SIG Unprimed 100/Pack. 357 SIG. Manufactured with high precision .357 SIG is a popular caliber among law enforcement professionals due to the easy to obtain material and reloading potential this brass has. The extra amount of virgin brass that is produced during the production process is essential in order for the reloading effort to be successful. Reloading can be tricky and time consuming but is well worth the effort when you have the correct components. This Winchester Brass is .357 SIG brass unprimed. Specifications for Winchester .357 SIG Unprimed Handgun Brass: Manufacturer: Winchester Caliber: .357 SIG Primed: No Brass Quantity: 100 Piece Cartridge Case Material: Brass Package Contents: Winchester Unprimed Handgun Shellcases 357 Sig Winchester WSC357SIGU: Handgun Brass .357 SIG Unprimed 100/Pack