Product Overview and Introduction

Maximize your big-bore AR-15 platform’s performance, stopping power, and reloading efficiency with Starline Unprimed Rifle Brass in 458 SOCOM. Engineered specifically to deliver devastating terminal energy, heavy-bullet momentum, and reliable feeding in standard AR-15 dimensions, Starline produces some of the toughest, most precise commercial brass available to handloaders.

Whether you are building a dedicated heavy-boar hunting upper, competing in big-bore tactical shooting matches, or ringing steel with massive 300-to-600 grain projectiles, Starline 458 SOCOM brass provides an uncompromised foundation for your reloading press.

Uncompromising Commercial Metallurgy and Big-Bore Durability

The 458 SOCOM cartridge was designed to pack the punch of a .458 Winchester Magnum into a package that fits a standard AR-15 magazine and receiver. Starline engineers its casings to handle the unique physical demands of this heavy-caliber semi-automatic platform:

• Strict Dimensional Uniformity: Rigorous quality control ensures consistent case length, rim dimensions, and internal volume, minimizing velocity spreads and ensuring reliable chambering.

• Large Pistol Primer Pocket Design: Manufactured with large pistol Boxer primer pockets matching original SAAMI specifications, providing reliable ignition for fast-burning rifle and pistol powders commonly used in the SOCOM cartridge.

• Superior Alloy Durability: Multi-stage thermal annealing and robust case head metallurgy create a tough casing that resists premature splitting, cracking, and primer pocket enlargement under heavy recoil and high operating pressures.

• Unprimed and Ready to Load: Supplied clean, polished, and unprimed, giving you total freedom to select your preferred primers, powder charges, and lead or monolithic solid bullets.

The Ultimate Foundation for Big-Bore AR Shooters

The 458 SOCOM is celebrated for its incredible close-to-medium-range knockdown power and versatility with cast or jacketed bullets. Starting with premium Starline brass ensures your handloaded ammunition chambers smoothly, extracts reliably, and performs consistently shot after shot.

Key Features and Benefits

• Commercial Grade Quality: Exceptional lot uniformity and wall concentricity compared to converted or makeshift brass.

• Large Pistol Primed: Standard large pistol primer pockets match original factory specifications.

• Exceptional Case Life: Tough alloy formulation withstands repeated high-pressure reloading cycles.

• Flexible Packaging Options: Available in convenient box quantities for hobbyists and high-volume big-bore shooters.

Specifications

• Product Type: Rifle Reloading Brass Casings

• Caliber: 458 SOCOM

• Condition: Unprimed, New Commercial Brass

• Primer Pocket Type: Boxer Primed (Large Pistol)

• Platform Compatibility: AR-15 Rifles and Custom Upper Receivers Chambered in 458 SOCOM

• Manufacturer: Starline Brass