RCBS AR Series Small Base Taper Crimp 2 Die Set .300 AAC Blackout

• Small Base Sizer Die: Sizes brass below standard full-length dimensions to improve chambering in semi-automatic rifles, helping reduce stoppages when reliable feeding matters most.
• 7-degree Taper Crimp Seater Die: Applies a taper crimp suited to autoloading rifle cartridges, helping prevent bullet movement during magazine recoil and feed-ramp impact.
• Built for AR-platform Reloading: The AR Series layout is intended for cartridges used in self-loading rifles, making it a practical choice for high-volume .300 AAC Blackout loading.
• Standard 7/8"-14 Thread: Fits common single-stage and progressive presses, so it integrates easily into established reloading setups without special adapters.
• Steel Die Construction: Hardened steel dies hold adjustment well and stand up to repeated use, which supports consistent case sizing and seating over long loading sessions.

About the AR Series Series

RCBS AR Series die sets are built for reloaders who prioritize dependable function in semi-automatic rifles, especially AR-platform firearms that cycle cartridges rapidly from the magazine into the chamber. Within the RCBS lineup, this series focuses on the needs of shooters loading for modern sporting rifles rather than traditional bolt-action applications. The defining feature is the use of a small base sizing die, which reduces case dimensions more aggressively than a standard full-length die to support smoother chambering in rifles with tighter or more demanding feeding cycles.

The series also pairs that sizing approach with a taper crimp seater die using RCBS’s 7-degree crimp angle. That design is well suited to autoloading rifle cartridges because it helps maintain cartridge shape and bullet retention without relying on a roll crimp style more common in other applications. In practice, AR Series dies are aimed at reloaders producing ammunition for training, field use, and general-purpose shooting where reliable feed, function, and fire are more important than a minimal-sizing approach. The result is a die family designed around repeatable setup, compatibility with standard presses, and ammunition that cycles with confidence in self-loading rifles.

About the RCBS AR Series Small Base Taper Crimp 2 Die Set .300 AAC Blackout

The RCBS AR Series Small Base Taper Crimp 2 Die Set .300 AAC Blackout is configured for reloaders who want dependable ammunition for .300 AAC Blackout rifles, including AR-platform carbines and other semi-automatic firearms chambered for this cartridge. Its two-die arrangement combines the operations most important to this role: full-length sizing and decapping in the small base die, followed by bullet seating and taper crimping in the seater die. That makes it especially practical for streamlined loading workflows where consistent cycling is a priority.

The small base sizing die is the key difference from a conventional rifle die set. By sizing the case body slightly more than a standard full-length die, it helps loaded rounds chamber more easily in self-loading rifles, which can be valuable when brass has been fired in different chambers or when the rifle is expected to run quickly and cleanly from the magazine. For .300 AAC Blackout, a cartridge often used in compact rifles and suppressed setups, that added margin can help maintain reliable operation across a wide range of loads.

The seater die uses a taper crimp rather than a roll crimp, which better suits ammunition intended for autoloading rifles. RCBS’s 7-degree taper crimp helps secure the bullet against movement during recoil and feeding while preserving cartridge geometry for smooth chamber entry. Combined with standard 7/8"-14 thread compatibility and durable steel construction, this set is well suited to reloaders who want a straightforward, robust tool for producing .300 BLK ammunition that feeds with confidence.

About RCBS

RCBS was founded in 1943 by Fred T. Huntington in Oroville, California. The company name comes from Rock Chuck Bullet Swage, the original bullet-swaging die that started the business. From that beginning, RCBS grew into a specialist in ammunition handloading equipment, with a product range that includes presses, dies, shell holders, powder measures, and priming tools.

RCBS manufactures reloading tools in Oroville, California and is known for serving both rifle and pistol reloaders with equipment that ranges from single-stage systems to turret and progressive presses. That long focus on practical reloading tools makes the brand especially relevant in die sets such as the AR Series, where precise machining, durable materials, and repeatable setup matter in everyday use.

Main Features

• Manufacturer: RCBS
• Made in: USA
• Pack size: 2 die set
• Die operation: Bullet seating, Decapping, Full length sizing, Taper crimping
• Die type: Standard
• Bushing: No
• Case body design: Bottle neck
• Case type: Boxer, Rifle
• Sizing die material: Steel
• Adjustment: Standard
• Press compatibility: Standard 7/8"-14 thread
• Bullet diameter: 7.85 mm / 309.00 inch
• Compatible calibers: .300 BLK, 7.62x35mm, .300 AAC Blackout, .300 Whisper

Warranty

2 years.

In the Box

• Small Base Sizer Die
• Taper Crimp Seater Die
• Black die box
• Printed instructions