The Hornady 00-7 Primer Cup Spring is a factory-original replacement component engineered for the priming arm assembly of select Hornady metallic reloading presses. Manufactured in the United States from high-tensile spring steel, this mechanical compression spring installs directly beneath the primer seater cup to maintain continuous upward tension. During ram stroke articulation, it prevents mechanical binding and guarantees positive, spring-loaded return cycling. Designed to replace worn, fatigued, or misplaced factory springs, it restores reliable seating performance across both small and large primer conversion setups.

Key Features

• OEM Mechanical Restoration: Delivers direct factory-spec upward tension beneath primer seating cups to ensure consistent primer retention and cycling.
• Dual Primer Size Compatibility: Seats under interchangeable cups to cycle 4.45 mm (0.175 in) small primers and 5.33 mm (0.210 in) large primers.
• Durable Spring Steel: Built from resilient high-tensile wire designed to withstand thousands of repetitive ram strokes without taking a permanent compression set.
• Press Assembly Integration: Designed specifically to integrate with Hornady primer seater punches and cups without requiring press modifications.

Specifications

• Manufacturer Part Number: 390007
• Product Type: Reloading press primer arm spring
• Country of Origin: United States
• Shipping Weight: 0.100 kg (0.106 lbs) including retail packaging
• Packaged Dimensions: 80 mm × 50 mm × 50 mm
• Interface Hardware Compatibility: Hornady Small Primer Cup (#390005), Large Primer Cup (#390006), Small Primer Punch (#390034), and Large Primer Punch (#390035)
• Press Compatibility: Hornady Lock-N-Load Classic Single Stage Press (#085001), Lock-N-Load Iron Press priming feed, and legacy Hornady 00-7, Pro-7, and Projector presses
• Operating Environment: Indoor workshop reloading bench

Who is the Hornady 00-7 Primer Cup Spring for?

• Hornady Lock-N-Load single-stage press reloaders — fits the integrated priming arms of the Lock-N-Load Classic and Iron presses, maintaining precise mechanical return beneath 4.45 mm small or 5.33 mm large primer seating assemblies to eliminate binding on every ram cycle.
• Legacy Hornady press operators — provides exact OEM mechanical restoration for vintage Projector, Pro-7, and 00-7 press primer arms, securing the 4.45 mm or 5.33 mm seating cup assembly during routine calibre conversions and overhaul maintenance.

Less suitable for: High-volume reloaders requiring throughput exceeding hundreds of rounds per hour or those priming .50 BMG cartridges; progressive reloading presses with integrated automatic primer tubes or dedicated heavy-calibre bench priming tools are better suited to these operations.