Mastering .300 Rem. Ultra Mag Reloading with the RCBS Full-Length 2-Die Set

For discerning shooters and handloaders who demand peak performance and precision from their firearms, especially those chambered in the powerful .300 Remington Ultra Magnum (.300 RUM), the process of reloading is not just a hobby—it's a science. Achieving consistent accuracy, optimizing ballistic performance, and enjoying significant cost savings over factory ammunition are core motivations. To unlock these benefits, having the right tools is paramount, and at the heart of any successful reloading setup are high-quality dies.

This comprehensive guide delves into the essential RCBS 17601 Full-Length 2-Die Set, Group A, specifically engineered for the .300 Rem. Ultra Mag. If you've ever wondered how to produce custom ammunition that outperforms off-the-shelf options, extend the life of your brass, or simply gain a deeper understanding of your cartridge's capabilities, this set is an indispensable asset.

Why Reload Your Own Ammunition, Especially for .300 RUM?

The .300 Remington Ultra Magnum is a formidable cartridge known for its flat trajectory, high muzzle velocity, and impressive energy, making it a favorite for long-range hunting and shooting. However, factory ammunition for such specialized calibers can be expensive, and finding loads tailored to your specific rifle and shooting needs can be challenging. This is where handloading shines.

Reloading empowers you to:

• Achieve Superior Accuracy: By fine-tuning components like bullet type, powder charge, and seating depth, you can develop loads that are perfectly matched to your firearm, leading to tighter groups and improved precision.
• Realize Significant Cost Savings: Once you invest in the initial equipment, the cost per round of handloaded ammunition is substantially lower than purchasing new factory loads, especially for powerful magnum cartridges like the .300 RUM. This allows for more practice and development without breaking the bank.
• Ensure Consistency and Reliability: You control every step of the process, ensuring uniform quality that often exceeds mass-produced ammunition. This consistency is crucial for predictable performance shot after shot.
• Extend Brass Life: Proper sizing and care during reloading can significantly extend the number of times a brass case can be reloaded, further contributing to cost efficiency.
• Customize for Specific Applications: Whether you're targeting varmints, large game, or aiming for sub-MOA groups at extreme distances, reloading allows you to tailor your ammunition to the exact requirements of the task.

The RCBS Full-Length 2-Die Set Group A .300 Rem. Ultra Mag is designed precisely for handloaders aiming to achieve these outcomes.

Understanding the Core Components: The Full-Length Sizer Die

The RCBS 17601 set includes two critical dies that work in tandem to prepare your fired brass for a new life. The first is the Full-Length Sizer Die with an Expander-Decapping Unit. This die is the workhorse of the initial reloading stages, addressing several vital functions simultaneously:

• Restoring Case Dimensions: After a cartridge is fired, the brass case expands to fit the rifle's chamber. For reliable feeding and consistent chambering in any rifle (not just the one it was originally fired in), the case must be resized back to its original, SAAMI (Sporting Arms and Ammunition Manufacturers' Institute) minimum cartridge dimensions. The RCBS Full-Length Sizer Die expertly achieves this, ensuring your reloaded rounds will chamber smoothly every time.
• Depriming: Integrated into the sizer die is the decapping pin, which efficiently pushes out the spent primer from the primer pocket. This prepares the case for a new primer.
• Neck Expansion: As the case is sized, the expander ball passes through the case neck, carefully expanding it to the precise internal diameter required to securely hold a new bullet. This critical step ensures proper neck tension, which is vital for consistent bullet seating and optimal powder burn.

One of the standout features of the RCBS Full-Length Sizer Die is its meticulous design for preventing common reloading issues. It incorporates vents specifically engineered to prevent case damage that can be caused by trapped air or excessive lubricant. This attention to detail minimizes the risk of dents or crumpling during the sizing process, preserving your valuable brass. Furthermore, headspace is held to minimum tolerances, ensuring that the critical case body length remains consistent during full-length sizing. This precision contributes directly to improved accuracy and extended case life, as it reduces unnecessary stress on the brass.

Understanding the Core Components: The Seater Die with Integrated Roll Crimper

The second die in the RCBS 17601 set is the Seater Die with Bullet Seater Plug. This die is where your efforts come to fruition, as it's responsible for the final assembly of your reloaded cartridge.

• Precise Bullet Seating: The primary function of the Seater Die is to accurately seat the bullet to your desired overall length (OAL). The Bullet Seater Plug is designed to cradle the bullet, pushing it smoothly and straight into the case neck without deforming the bullet tip. Achieving consistent OAL is crucial for accuracy, as it affects chamber pressure and bullet jump.
• Integrated Roll Crimper: A significant advantage of this RCBS Seater Die is its built-in roll crimper. This feature allows you to secure the bullet in the case at the same time it is seated. Crimping adds an extra layer of bullet retention, which is particularly beneficial for magnum cartridges like the .300 RUM, where heavy recoil could potentially cause bullets to move forward in the case. A good crimp ensures bullet stability during feeding and firing, contributing to reliable performance and safety.

This two-in-one functionality streamlines your reloading process, saving time and ensuring uniform bullet seating and crimping, which are vital for consistent performance from your .300 RUM handloads.

Why Choose RCBS for Your .300 RUM Reloading Needs?

RCBS has been a trusted name in reloading equipment for decades, synonymous with quality, innovation, and durability. When you invest in an RCBS die set like the 17601, you are investing in:

• Legendary Durability: RCBS dies are renowned for their robust construction, typically made from heat-treated steel, designed to withstand countless reloading cycles. This means your investment will last for years, delivering reliable performance batch after batch.
• Precision Engineering: Every RCBS die is manufactured to exacting tolerances, ensuring that your cases are sized accurately and your bullets are seated consistently. This precision is directly translated into the accuracy of your reloaded ammunition.
• Ease of Use: While precision tools, RCBS dies are designed with the user in mind, making them relatively straightforward to set up and operate, even for those new to handloading. Clear instructions and intuitive design minimize the learning curve.
• Proven Performance: Millions of reloaders worldwide trust RCBS for their ammunition needs. Their products are battle-tested and proven to deliver consistent, high-quality results, which is essential when dealing with powerful cartridges like the .300 Rem. Ultra Mag.
• Comprehensive Support: RCBS stands behind its products with excellent customer service and resources, providing peace of mind to reloaders.

The RCBS 17601 Full-Length 2-Die Set is a testament to the brand's commitment to quality, offering the precision and reliability necessary for optimizing .300 RUM performance.

Who Benefits Most from the RCBS 17601 .300 RUM Die Set?

This die set is an ideal choice for a wide range of handloaders, from those just beginning their journey into precision reloading to seasoned veterans seeking to maximize their .300 RUM rifle's potential:

• Precision Shooters: Individuals focused on achieving sub-MOA accuracy for competitive shooting or ethical hunting will appreciate the ability to control every variable of their ammunition.
• Long-Range Enthusiasts: The .300 RUM thrives at extended distances, and custom loads crafted with precise dies are crucial for hitting targets hundreds or even thousands of yards away.
• Hunters of Large Game: For hunters relying on the .300 RUM for big game, producing custom, reliable, and powerful loads ensures ethical kills and confidence in the field.
• Cost-Conscious Shooters: Given the expense of factory .300 RUM ammunition, this die set is a cornerstone for anyone looking to save money while enjoying more trigger time.
• Those Seeking Component Optimization: Reloaders who want to experiment with different bullet weights, powder types, and primer combinations to find the ultimate load for their specific rifle.

Achieving Optimal Performance with Your RCBS Dies

To get the most out of your RCBS 17601 Full-Length 2-Die Set and produce exceptional .300 Rem. Ultra Mag ammunition, consider these best practices:

1. Clean Your Brass Thoroughly: Before sizing, ensure your fired cases are clean. Tumbling or ultrasonic cleaning removes carbon and debris, preventing scratches inside your dies and extending their lifespan.
2. Proper Lubrication: Full-length sizing requires a thin, even coat of case lubricant. RCBS offers excellent case lubes. Apply sparingly to avoid dents or excess lube dimples on the case shoulder.
3. Correct Die Setup: Follow the RCBS instructions precisely for setting up both the sizer and seater dies on your reloading press. Incorrect setup can lead to inconsistent sizing, improper bullet seating, or even damage to your brass or dies.
4. Monitor Headspace: While the RCBS sizer die maintains minimum headspace tolerances, occasionally checking your reloaded cases with a headspace gauge can confirm proper sizing and prevent issues.
5. Experiment with Seating Depth: For optimal accuracy, experiment with different bullet seating depths in your rifle. Even small adjustments can significantly impact group sizes. Always consult reliable reloading manuals for safe starting and maximum depths.
6. Regular Die Maintenance: Keep your dies clean. After each reloading session, wipe them down to remove any lubricant residue or brass shavings. A light coat of rust preventative can be beneficial for long-term storage.

By adhering to these principles and leveraging the precision engineering of the RCBS 17601 Full-Length 2-Die Set, you will consistently produce high-quality .300 RUM ammunition that meets your most demanding performance requirements. This set represents a foundational component for any serious reloader looking to maximize their shooting experience and investment. Available at trusted retailers like DEGuns, this die set is ready to become the heart of your .300 RUM reloading bench.

Product Specifications Overview

Feature	Detail
Brand	RCBS
Series	Group A
Model	Full-Length 2-Die Set
Caliber	.300 RUM
Die Type	Sizer / Seater
Gun Type	Rifle
Dies In Set	2
SKU	64944
MPN	17601
UPC	076683176011