Lyman Neck Expanding (M) Die 9mm Luger/.380 ACP

The Lyman Neck Expanding (M) Die for 9mm Luger/.380 ACP is a purpose-built handgun reloading die that addresses one of the most overlooked steps in ammo assembly: proper case mouth prep. Unlike standard expander buttons that stretch brass, this two-step neck expanding die flares and opens the case mouth without unnecessary work-hardening, which means your brass stays in the game longer. For handloaders who shoot cast bullets, this die prevents the frustrating "shaving" that happens when undersized case mouths shred jacket or lead during seating—a problem that costs both accuracy and wasted projectiles.

Built from hardened steel heat-treated to Rc 50 hardness and hand polished to an 8 RMS finish before and after treatment, this die is engineered to last. The two-step design creates a gentler expansion profile that seats bullets consistently without the metal fatigue of conventional methods. Whether you're loading jacketed or cast rounds for range work, hunting, or match prep, neck expanding as a separate operation pays dividends in consistency and case longevity.

This is a die only—you'll need to pair it with your existing press and shellholder. Reload smarter, not harder, and keep your brass cycling through more reloads.

Key Features

• Two-step neck expanding process reduces case stretching and extends brass life
• Prevents bullet shaving when loading cast projectiles
• Hardened steel construction, heat-treated to Rc 50
• Hand polished before and after heat treatment for precise tolerances
• Sized for 9mm Luger and .380 ACP

Specifications

Frequently Asked Questions

Will this die work with my existing reloading press?

The Lyman neck expanding die is designed as a standard reloading die, but you'll need to verify compatibility with your specific press and confirm you have an appropriate shellholder (not included) for 9mm Luger or .380 ACP.

What's the difference between neck expanding and a standard expander button?

A standard expander button stretches the case mouth during sizing, which work-hardens the brass. The two-step neck expanding process flares the case mouth without that excessive stretching, allowing your brass to be reloaded more times before it becomes fatigued and unsafe.

Will this die help with cast bullet loads?

Yes. By properly opening the case mouth before seating, it prevents the "shaving" that occurs when bullets are forced into undersized case mouths, protecting both your cast projectiles and improving load consistency.

Does this come with a shellholder?

No, the shellholder is sold separately. You'll need the appropriate shellholder for 9mm Luger or .380 ACP to use this die.