The Sellier & Bellot 5.3 LRM Large Rifle Magnum Boxer Primers (Product Code: V361627) are centrefire reloading components engineered for consistent, heavy-charge ignition. Designed with an integral anvil for standard de-capping in reloadable Boxer-primed cartridge cases, each primer delivers a hotter flame temperature, greater volume, and higher brisance than standard non-magnum options. This extended ignition spark facilitates the complete and uniform combustion of large powder charges and slow-burning extruded or spherical propellants in large-capacity rifle cases.

Key Features

• Consistent Magnum Ignition: Utilises a non-corrosive, non-mercuric priming composition engineered to produce a higher flame volume and brisance, ensuring positive ignition of slow-burning propellants.
• Centrefire Boxer System: Incorporates an internal single-flash-hole anvil, allowing straightforward de-capping and uniform seating in commercial Boxer-primed brass cases.
• Standard Large Pocket Sizing: Manufactured with an exact 5.3 mm cup diameter to ensure an interference fit in standard large rifle cartridge pockets.

Specifications

• Product Code: V361627
• Primer Type: Centrefire Boxer (Large Rifle Magnum)
• Cup Diameter: 5.3 mm (~0.210 in)
• Weight per Unit: Approximately 0.35 g
• Carton Weight: Approximately 0.55–0.56 kg per 1,000-count carton
• Priming Mixture: Non-corrosive, non-mercuric formulation
• Packaging Format: 100-count trays, 1,000-count cartons (10 × 100 trays), and 5,000-count outer cases
• Cartridge Compatibility: Large Rifle primer pockets in magnum calibres, including .300 Winchester Magnum, 7mm Remington Magnum, and .338 Winchester Magnum

Who is the Sellier & Bellot 5.3 LRM Large Rifle Magnum Boxer Primers for?

• Big-game hunters loading magnum calibres — Requires the 5.3 mm cup diameter and magnum-level brisance of this large rifle magnum primer to ensure reliable powder ignition across large-volume cases like the .300 Winchester Magnum and 7mm Remington Magnum.
• PRS and F-Class precision target shooters — Relies on the uniform 0.35 g weight per unit and high-volume flame profile of this large rifle magnum primer to maintain shot-to-shot combustion consistency with dense, slow-burning propellants.

Less suitable for: Standard non-magnum calibres such as .308 Winchester or .30-06 Springfield that use fast-to-medium burn powders, as well as cases with 4.4 mm primer pockets; standard large rifle primers or standard small rifle primers suit these respective loads better without risking unnecessary chamber pressure elevation.