The Redding 338 Cal. Carbide Size Button Kit replaces standard factory steel expander balls with a hard, polished tungsten carbide expander for metallic cartridge reloading. Designed to fit standard Redding bottleneck sizing rods, this assembly features a free-floating design that allows the button to self-center within the cartridge neck during the sizing stroke. This floating action minimizes brass neck stretch and reduces concentricity runout, while the polished carbide surface allows smooth inside-neck expansion without the need for dedicated internal neck lubricants.

Key Features

• Lube-Free Expansion: Polished tungsten carbide surface eliminates the requirement for inside-neck sizing lubrication, streamlining brass preparation for bottleneck cases.
• Self-Centering Floating Design: Floats freely on the decapping rod assembly rather than locking rigidly, allowing natural alignment inside the case neck to reduce overall neck runout.
• Wear-Resistant Material: Tungsten carbide construction prevents galling, scratching, and abrasive wear caused by carbon fouling inside fired case necks.
• Complete Assembly Kit: Includes the free-floating carbide expander button, a decapping pin retainer adapter, and a spare decapping pin (decapping rod sold separately).

Product Specifications

• Calibre: .338 Calibre (8.58 mm nominal diameter)
• Material: Polished tungsten carbide expander with steel adapter components
• Packaged Weight: Approximately 0.05 lb (23 g)
• Die Compatibility: Redding Full-Length Sizing Dies, Standard Neck Sizing Dies, and Type S Bushing Dies

Who is the Redding 338 Cal. Carbide Size Button Kit for?

• Long-range ELR competitors — handles high-volume brass preparation for .338-class magnums by using a nominal 8.58 mm (.338 calibre) free-floating carbide expander to reduce case neck runout and maintain consistent neck tension without requiring inside-neck lube.
• Big-game hunters — streamlines the handloading process for heavy cartridges such as .338 Lapua Magnum and .338 Winchester Magnum by integrating an 8.58 mm nominal diameter polished carbide button that eliminates internal neck galling and friction.
• Precision rifle shooters — upgrades standard Redding sizing dies with an ultra-hard .338 calibre carbide sizing button assembly weighing just 23 g (0.05 lb) that resists abrasive carbon wear over thousands of sizing cycles.

Less suitable for: Handloaders running Redding Competition Neck Sizing Dies, which require dedicated competition-series carbide buttons due to proprietary rod geometry, or reloaders forming cases other than .338 calibre (8.58 mm) bottleneck cartridges, who require calibre-specific expander button kits.