Hornady Custom Grade 300 Remington Ultra Magnum Bullet Seater Die

The Hornady Custom Grade 300 Remington Ultra Magnum bullet seater die is built for reloaders who demand precision and reliability with one of the most potent magnum cartridges on the market. This seater die is engineered to handle the demands of 300 RUM reloading—a caliber favored by long-range hunters and competitive shooters pushing heavy projectiles downrange. Hornady's Custom Grade construction uses select, heat-treated steel designed to withstand thousands of reloading cycles without wearing out or breaking under normal use, backed by their lifetime durability guarantee.

What sets this seater die apart is its sliding alignment sleeve, a feature that keeps the bullet, case mouth, and seater stem perfectly aligned as the round is seated. This alignment precision is critical when working with magnum rounds, where consistency directly impacts velocity and shot-to-shot repeatability. The die also includes a built-in crimp ring—you can engage it for a secured crimp or leave it raised if your process calls for no crimp, giving you flexibility in your reloading protocol.

Setup is straightforward: the die arrives with Hornady's double-flat die lock rings already installed, eliminating a common assembly step. Everything comes packaged in Hornady's custom plastic die box, ready to slot into your press. Whether you're fine-tuning loads for a long-range rifle or working up fresh rounds for the field, this seater die provides the precision alignment and build quality that magnum reloading demands.

Key Features

• Sliding alignment sleeve for bullet, case mouth, and seater stem alignment
• Heat-treated select steel construction designed for a lifetime of use
• Built-in crimp ring—engage for crimp or raise for no-crimp reloading
• Double-flat die lock rings pre-installed
• Custom plastic storage box included
• Hornady lifetime durability guarantee under normal use

Specifications

Frequently Asked Questions

What's included with this 300 RUM seater die?

The die comes complete with double-flat Hornady die lock rings already installed, plus a custom plastic die box for storage and organization.

Can I use this die without a crimp, or do I have to crimp every round?

The built-in crimp ring can be engaged when you need a crimp or raised if your reloading process doesn't call for one. You control whether crimp is applied.

How durable is this Hornady die for heavy magnum reloading?

Hornady's Custom Grade seater die is made from heat-treated, select steel and is guaranteed never to wear out or break under normal reloading use, regardless of volume.

What does the sliding alignment sleeve do?

The sliding alignment sleeve holds the bullet, case mouth, and seater stem in precise alignment before the bullet enters the case, ensuring consistent seating depth and bullet concentricity—critical for magnum accuracy.