Hornady Mandrel — Neck Turn Tool, 6mm (.243)
Part #: 391913 • UPC: 090255919134 • Caliber: 6mm (.243) • Type: Neck-Turn mandrel (for Hornady Neck Turn Tool body, sold separately)
Unlock next-level case concentricity and uniform neck tension for your 6mm loads with the Hornady 6mm Mandrel for the Neck Turn Tool. Purpose-built for precision reloaders, this caliber-specific mandrel supports the inside of the case neck while you turn the exterior, helping you achieve uniform neck-wall thickness, better bullet alignment, and repeatable seating tension across lots. Whether you’re chasing single-digit SDs for 6mm Creedmoor, ringing steel with .243 Win, or tuning a 6mm ARC match rifle, Hornady’s 6mm mandrel gives your brass the consistent foundation it needs.
Why Precision Shooters Choose Hornady Mandrels
Caliber-Correct Support: Sized specifically for 6mm/.243 case necks to center the neck on the tool and minimize runout during cutting.
Uniform Neck Walls: A correctly supported neck lets the cutter remove high spots without collapsing the neck, yielding even thickness and more consistent neck tension.
Improved Concentricity: Better neck uniformity promotes truer bullet-to-bore alignment, aiding lower ES/SD and tighter groups.
Match-Grade Repeatability: Mandrel-guided turning helps brass behave the same round after round—key for long-range dope you can trust.
Hornady Quality: Precision-machined from durable steel for smooth operation and long service life.
Key Features & Specs
Product: Hornady Mandrel for Neck Turn Tool
Caliber: 6mm (.243)
Function: Internal support/pilot for case necks while turning exterior neck surface
Compatibility: Fits the Hornady Neck Turn Tool body/assembly (tool sold separately)
Use Cases: Precision reloading for 6mm Creedmoor, .243 Winchester, 6mm ARC, 6×47 Lapua, 6 BR family, and other cartridges using 6mm bullets*
Part #: 391913
UPC: 090255919134
*Always verify neck dimensions, chamber specs, and brass thickness for your specific cartridge before turning.
What Neck Turning with a Mandrel Delivers
Consistent Neck Tension: Even wall thickness yields predictable expansion on firing and repeatable grip on the bullet at seating.
Cleaner Seating Feel: Straighter, more uniform necks provide smoother press feel and straighter bullets with less runout.
Extended Brass Life: By eliminating heavy high spots, you can reduce work-hardening in specific areas and help even out wear over multiple firings.
Better Long-Range Results: More consistent ammo = tighter vertical and more reliable dope at distance.
Quick Start: Using the 6mm Mandrel (Overview)
Prep Brass: Size and lightly expand if needed to ensure a slip-fit over the mandrel; chamfer inside necks.
Install Mandrel: Insert the 6mm mandrel into the Hornady Neck Turn Tool body per the manufacturer’s instructions.
Set Cutter Depth: Start with a conservative cut; aim to kiss high spots and sneak up on your target neck thickness.
Turn Evenly: Rotate smoothly while keeping steady, light pressure; the mandrel centers the neck as the cutter skims the exterior.
Measure & Verify: Use a ball micrometer or tubing mic to confirm uniform thickness around the neck; adjust and repeat as needed.
Final Prep: Deburr/chamfer lightly and proceed to priming and seating.
Pro Tips for Best Results
Match Bushing to Finished Thickness: If you use bushing dies, choose a bushing that matches your final neck OD minus bullet diameter for ideal tension.
Anneal on Schedule: Periodic annealing promotes consistent spring-back, especially helpful after turning and multiple firings.
Measure Often: Check wall thickness at 12/3/6/9 o’clock on several cases to confirm uniformity across your lot.
Go Light: Remove only what you need to true the neck—minimal cuts protect brass life and maintain strength.
Compatibility & Safety
Designed for the Hornady Neck Turn Tool system (mandrel component only).
Confirm case neck thickness, chamber clearance, and your target finished dimension before material removal.
Wear eye protection and keep cutting surfaces clean for consistent results.
Frequently Asked Questions
Q: Will this mandrel work with 6mm ARC and 6mm Creedmoor?
A: Yes—if your brass uses 6mm (.243) bullets, the 6mm mandrel provides the correct internal support for neck turning. Always verify your neck thickness targets and chamber specs.
Q: Do I need to expand necks before turning?
A: Neck inside diameter should slip over the mandrel without excessive force. A light expand/mandrel pass after sizing typically ensures a smooth fit.
Q: How much should I cut?
A: Many precision shooters remove just enough to clean up high spots (often .001–.002" total on thickness). Let your chamber, bushing, and accuracy goals guide the final number.
Q: Does this include the full Neck Turn Tool?
A: No—this is the 6mm mandrel only. The Hornady Neck Turn Tool body/cutter is sold separately.
SEO Highlights (Quick Scan)
Hornady 6mm Neck Turn Tool Mandrel — caliber-specific pilot for case neck support
Improves neck-wall uniformity, concentricity, and neck tension for precision reloading
Compatible with Hornady Neck Turn Tool (tool sold separately)
Ideal for 6mm Creedmoor, .243 Win, 6mm ARC and other 6mm cartridges
Part 391913, UPC 090255919134
Tune your brass like a pro with the Hornady 6mm Mandrel (391913)—the essential Neck Turn Tool component that delivers uniform necks, consistent tension, and match-grade performance from the first sighter to the last shot.
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