The Sellier & Bellot 8x57 JS Mauser Unprimed Rifle Cartridge Brass Cases provide new, reloadable brass cartridge cases for precision handloading and custom ammunition assembly. Manufactured to standard C.I.P. dimensions, each case features a rimless profile, a maximum case length of 57.00 mm, and is dimensioned to seat standard .323 in (8.20 mm) diameter projectiles. As an inert, unprimed reloading component, these cases feature factory-annealed necks and shoulders to improve ductility and extend fatigue life across multiple reloading cycles.

Key Features:

• Boxer Primer Pocket: Utilises standard Large Rifle Boxer primer pockets with a single flash hole, avoiding the complex decapping equipment required by Berdan-primed military surplus cases.
• Factory Annealing: Necks and shoulders are factory heat-treated to prevent premature neck-splitting and maintain structural ductility through repeated resizing cycles.
• Standard Dimensions: Built to C.I.P. specifications with a maximum 57.00 mm case length, an 11.95 mm base diameter, and an 11.95 mm rim diameter.
• High-Pressure Capability: Engineered to operate safely up to the C.I.P. maximum service pressure limit of 3,900 bar (approx. 56,565 psi) when following published reloading data.
• Reloading Preparation: Cases are supplied unprimed in 20-piece packs, requiring initial full-length resizing, deburring, and lubrication prior to loading.

Specifications

• Manufacturer Part Number: V337602
• Calibre: 8x57 JS (8mm Mauser / 8x57 IS)
• Pack Size: 20 pieces
• Case Type: Rimless, unprimed brass
• Primer Pocket: Large Rifle Boxer
• Maximum Case Length: 57.00 mm
• Bullet Diameter Compatibility: .323 in (8.20 mm)
• Maximum Service Pressure: 3,900 bar (C.I.P.)

Who is the Sellier & Bellot 8x57 JS Mauser Unprimed Brass Cases 20 Pack for?

• Handloaders loading custom ammunition for modern or historic 8x57 JS sporting rifles — seats .323 in (8.20 mm) projectiles within a standardized 57.00 mm maximum case length to assemble hunting or target loads within safe C.I.P. pressure limits up to 3,900 bar using this 20-piece unprimed rifle brass case pack.
• Shooters seeking to avoid military surplus depriming — features a single-flash-hole Large Rifle Boxer primer pocket that eliminates the specialized tools required for Berdan-primed surplus brass, providing a conventional reloading cycle for 8x57 JS unprimed brass cases.

Less suitable for: Firearms chambered in earlier .318-inch bore 8x57 J / I rifles (where firing .323-inch projectiles creates dangerous pressure spikes exceeding 3,900 bar) or break-action drillings requiring rimmed cases; these applications require dedicated .318-bore brass or rimmed 8x57 JRS cases.