The RCBS Neck Sizer Die for .300 Remington Ultra Magnum (.300 RUM) (RCBS part no. 17630) sizes only the neck of a fired case, leaving the body and shoulder untouched. Made by RCBS, this die is crafted from steel and backed by RCBS’s lifetime guarantee. Because only the neck is resized, there’s just enough tension to hold the bullet firmly in place, which extends case life and can improve accuracy for handloaders shooting the same rifle’s fired brass, an especially useful savings on a magnum case like this one.

Key Specifications

• Sized specifically for .300 Remington Ultra Magnum (.300 RUM) cartridges.
• Sizes only the case neck, leaving the body and shoulder unsized.
• Extends case life by minimizing brass working compared to full-length sizing.
• Machined from steel for durability.
• Backed by RCBS’s lifetime guarantee on materials and workmanship.

Frequently Asked Questions

How is neck sizing different from full-length sizing? Neck sizing resizes only the case neck, leaving the body and shoulder as fired, which extends case life and can improve accuracy in a single rifle.

Why does neck sizing matter more on a magnum case? Magnum brass like .300 RUM is more expensive to replace, so minimizing case working with neck-only sizing helps stretch its usable life.

Buy the RCBS Neck Sizer Die .300 RUM

Stretch the life of your .300 RUM brass and tighten up your accuracy. Order this die from our Lubbock, Texas gun shop for fast, direct shipping, and browse the rest of our reloading dies selection.