The Redding 300 Win Mag Competition Bushing Neck Die Set (MPN: 58153) is a precision 3-die handloading system engineered specifically for .300 Winchester Magnum cartridge brass. Designed to achieve tight concentricity and minimise total indicated runout (TIR), this die set provides match-grade neck tension control, full-length case body resizing without disturbing the neck, and micrometer-adjustable bullet seating.

Key Features

• Sliding Sleeve Alignment: Both the Competition Bushing Neck Sizing Die (Part #56153) and Competition Seating Die (Part #55153) utilise internal, precision-ground sliding sleeves that align and fully support the case body before and throughout sizing and seating operations.
• Micrometer Depth Adjustments: The neck die and seating die feature micrometer adjustment heads calibrated in 0.001" increments to precisely control the length of the sized case neck and seating depth.
• Dedicated Body Resizing: Includes a dedicated Body Die (Part #75153) to resize the case body and bump the shoulder back on fire-formed cases without making contact with the case neck.
• Interchangeable Bushing Design: Uses standard Redding neck sizing bushings (typically .330" to .338" diameter for .300 Win Mag; sold separately) to set exact neck tension without over-working the cartridge brass.

Product Specifications

• Calibre Compatibility: .300 Winchester Magnum (.308 in / 7.62 mm bullet diameter)
• Die Set Type: 3-Die Set (Competition Bushing Neck Die #56153, Body Die #75153, Competition Seating Die #55153)
• Thread Interface: Standard 7/8"-14 reloading press threading
• Required Shellholder: Redding #6 (Shellholder #11006 or Competition Shellholder #11606)
• Adjustment Increments: 0.001" micrometer gradations
• Packaged Shipping Weight: Approximately 0.9 kg to 1.1 kg
• Operation: Manual, mechanical handloading tool

Who is the Redding 300 Win Mag Competition Neck Die Set for?

• Competitive F-Class and Benchrest Shooters — Requires this 3-die set to eliminate bullet runout and precisely adjust bullet seating depths and neck sizing in 0.001" micrometer increments for match-grade .300 Winchester Magnum competition rifles.
• Long-Range Precision Rifle Hunters — Relies on this 300 Win Mag reloading die set using standard 7/8"-14 press threads and a Redding #6 shellholder to maintain fire-formed brass dimensions and uniform neck tension for dedicated bolt-action rifles.

Less suitable for: Reloaders feeding semi-automatic or pump-action rifles, or loading for multiple different firearms chambers, which require a standard full-length sizing die instead of a bushing neck sizing die to guarantee reliable feeding and cycling.