The RCBS 3-Die Roll Crimp Set (Model: R20604) is a manual mechanical reloading tool designed specifically for processing straight-walled .375 Winchester rifle cartridges. Built as part of the RCBS Group C product line, this three-die assembly allows handloaders to resize, expand, seat, and roll crimp cases for lever-action and other .375 Win rifles. The dies are machined from polished, hardened steel and feature standard threads to integrate with existing workshop reloading setups.

Key Features

• Three-Die Sizing and Seating System: Includes a hardened steel sizer die with an integrated decapping unit to deprime and resize cases, a dedicated expander die to flare case mouths, and a seating die that applies a finished roll crimp.
• Roll Crimp Integration: The seating die features a built-in roll crimper designed to roll the case mouth directly into the bullet's cannelure, preventing projectile setback during recoil in tubular magazines.
• Standard Thread Mounting: Machined with 7/8"-14 thread sizing to ensure compatibility with most standard single-stage and turret reloading presses.
• Protective Packaging: Shipped in the signature RCBS green plastic storage box to protect the precision-ground steel components from environmental dust and damage when not in use.

Product Specifications

• Model Number: R20604 (also cataloged as 20604)
• Compatible Caliber: .375 Winchester (.375 Win)
• Die Classification: Group C (Straight-Walled Rifle Cartridges)
• Thread Size: 7/8"-14
• Material: Hardened, polished steel
• Crimp Style: Roll crimp
• Required Shellholder: RCBS Shellholder #2 (not included; sold separately)
• Power Requirements: None (manual operation)

Who is the Rcbs 375 Win 3 Die Set for?

• Lever-action rifle handloaders — who reload .375 Winchester ammunition and require standard 7/8"-14 thread size compatibility to produce rounds that resist physical bullet setback inside tubular magazines under spring tension.
• Precision ammunition customizers — who require a Group C straight-wall die set with 7/8"-14 thread size to perform exact, multi-stage case expanding and roll crimping of .375 Winchester brass.

Less suitable for: Handloaders who require dry-sizing capabilities without case lubrication, as the hardened steel sizing die in this RCBS 3-die set requires manual case lubrication to prevent stuck cases, nor is it suitable for rimless semi-automatic cartridges that require a taper crimp instead of a roll crimp to headspace correctly on the case mouth.