The Redding Competition Bullet Seating Die for .300 Remington Ultra Magnum (.300 RUM) is a benchrest-grade reloading die engineered to seat .308 in (7.82 mm) diameter projectiles with extreme concentricity and repeatable depth. Built with an industry-standard 7/8"-14 thread interface to fit standard single-stage and progressive reloading presses, this mechanical seating die integrates a precision-ground, tight-tolerance sliding alignment sleeve and a free-floating seating stem to align the cartridge case and bullet prior to seating, minimising Total Indicated Runout (TIR).

• Precision-Ground Alignment Sleeve: Fully supports and centres the .300 RUM cartridge case and bullet along a straight line before seating begins.
• Free-Floating Seating Stem: Patented floating design eliminates radial play to reduce bullet runout and concentricity errors.
• Top-Mounted Micrometer Adjustment: Features a calibrated micrometer head adjustable in 0.001 in increments with an adjustable zero-reset function for fine-tuning Cartridge Overall Length (COAL).
• Broad Press Compatibility: Uses standard 7/8"-14 threading to mount directly into standard Australian-market reloading presses.

Specifications

• Calibre Compatibility: .300 Remington Ultra Magnum (.300 RUM)
• Bullet Diameter: .308 in (7.82 mm)
• Thread Interface: 7/8"-14 standard thread
• Micrometer Adjustment Increments: 0.001 in
• Included Seating Stem: Standard Profile Stem (#55030)
• Compatible Shellholders: Redding #6 Shellholder (#11006) or Competition Shellholder (#11606) (sold separately)
• Operation: Fully mechanical

Who is the Redding Competition Seating Die for .300 RUM for?

• Long-range precision shooters loading .300 RUM — Handloaders adjusting bullet seating depth in exact 0.001 in increments on the micrometer head to fine-tune jump distance for .308 in (7.82 mm) projectiles in full-size .300 RUM chambers.
• F-Class and benchrest competitors shooting magnum cartridges — Match reloaders using this competition bullet seating die with standard 7/8"-14 threaded presses to eliminate radial runout and achieve consistent, straight-line bullet alignment on large-capacity .300 Remington Ultra Magnum cases.
• Extreme-range hunters handloading match-grade .300 RUM ammunition — Reloaders who require precise Cartridge Overall Length adjustments down to 0.001 in increments for .308 in (7.82 mm) diameter hunting bullets in high-velocity .300 RUM rifles.

Less suitable for: Handloaders processing shorter .300 magnums (such as .300 WSM, .300 SAUM, or .300 Win Mag) who require a shorter, calibre-specific seating sleeve, or shooters needing an integrated crimp function, who should use a dedicated standard crimping die or a roll/taper crimp seating die.