Lee Precision 300 Win Mag Rifle Precision Micrometer Bullet Seating Die

The Lee Precision 300 Win Mag Rifle Precision Micrometer Bullet Seating Die brings repeatable, dead-length seating to your 300 Winchester Magnum handloads without the price tag of boutique reloading equipment. If you're stepping up from basic dies to dial-in your seating depth to the thousandth of an inch, this micrometer-equipped die reads like a precision depth gauge and lets you dial in exactly where you want that bullet seated—then lock it in and forget it. The floating bullet guide keeps cases and bullets perfectly aligned through the seating stroke, which means consistent runout and uniform seating depth across your entire batch.

The design handles nearly any bullet point style without marking or deformation, thanks to a machined and burnished seating stem. The reversible floating bullet guide is a Lee exclusive: unthread it and flip it to set up simultaneous seating and crimping in a single press stroke if your load recipes call for it. That flexibility saves you a separate crimping pass and simplifies your press setup. The laser-engraved micrometer thimble and body dial in thousandths of an inch with easy-to-read graduations, so there's no guesswork about where your bullets are going to land depth-wise.

This is a purpose-built die for serious reloaders who want precision seating without leaving the bench and wasting time on trial-and-error adjustments. Whether you're loading match ammunition, hunting rounds, or experimenting with different seating depths for velocity tuning, the infinitely adjustable micrometer gives you the control to dial in your ideal setup.

Key Features

• Micrometer adjustment calibrated in one-thousandth-inch increments for precise bullet seating depth
• Floating bullet guide maintains perfect case-to-bullet alignment and minimizes runout
• Dead-length seating: case body contacts shell holder for uniform seating depth
• Reversible guide allows simultaneous seating and crimping in a single stroke
• Machined and burnished seating stem handles all bullet point styles without marking
• Laser-engraved markings for easy reading and repeatability

Specifications

Frequently Asked Questions

Can I use this die for both seating and crimping?

Yes. The floating bullet guide is reversible—unthread it and reinstall it in the opposite orientation to set up simultaneous seating and crimping. This is an exclusive Lee feature and lets you complete both steps in a single press stroke.

How precise is the micrometer adjustment?

The micrometer is calibrated in one-thousandth-inch (0.001") increments and is infinitely adjustable. Once you dial in your desired seating depth, you can repeat that exact setting on every round.

Will this die mark or damage my bullets?

No. The seating stem is machined and burnished specifically to seat nearly any bullet point style without marking or deformation.

What makes the floating bullet guide important?

The floating bullet guide holds the case mouth and bullet in perfect alignment during the seating stroke, which minimizes bullet runout and ensures uniform seating depth across your entire batch. The radial clearance in the guide allows the case and guide to self-align with the seating screw.