Modular Sizing Die – BR

After studying precision CNC machines and tooling, we designed the Modular Sizing Die with shallow tapers instead of threads to precisely center and secure the Solid Decapping Pin. This tapered geometry provides unparalleled concentricity and repeatability.

Additionally, we designed the cartridge sizing geometry to size slightly more at the base and less at the shoulder than most resizing dies. This sizing profile minimizes case runout, reduces brass stress, and helps eliminate extraction issues in properly sized rifle chambers.

Modular Sizing Die Assembly

• Modular Sizing Die Body: Standard 7/8 x 14 threads, 17-4 Stainless Steel, with a Salt Bath Nitride finish for improved lubricity and performance compared to other resizing dies.
• Universal Solid Decapping Pin: High-strength construction from 1144 Stress Proof Steel, with a .058” nominal diameter pin tip to fit small primer flash holes. You can adjust the pin tip protrusion by moving the wide-mouth retaining clip.
• Knurled ER11 Top Cap: ¾ x 24 Threads that secure the ER11 Top Cap into the die body, compressing the ER11 collet and ensuring top concentricity for the Decapping Pin or Expander Mandrel.
• ER11 Collet: Commercially available ER11 collet to accommodate various Decapping Pin and Expander Mandrel diameters.
• Taper Adapter: When the Knurled ER11 Top Cap is threaded into the die body, it seats the ER11 Collet into the Taper Adapter, securing the Decapping Pin or Expander Mandrel. The Taper Adapter sits directly above the Neck / Shoulder Sizing Bushing, allowing the Bushing to float.
• Neck / Shoulder Bushings: Available in multiple caliber-specific neck diameters. You can add .001” shims above the Neck/Shoulder Bushing to adjust headspace without threading the die in or out.

Setting Up Your Short Action Customs Modular Sizing Die

• Clean the inside of the resizing die thoroughly. A .40 caliber plastic pistol brush with a 12-gauge shotgun patch works well for cleaning out the die body.
• Assemble the Modular die as shown in the image below.
• With the reloading press ram fully up, thread the resizing die into the top of the press until it touches the shell holder. Lower the ram, then thread the die down slightly to achieve a “cam over” effect with the press. Tighten the die body lock ring. For Area 419 Zero Press users, thread in the die about 1/8″ after it touches the shell holder.
• Use a headspace comparator to measure the fired brass headspace by contacting the shoulder of the brass.
• Lubricate a piece of clean, fired brass and cycle it through the Modular Sizing Die using a smooth, consistent ram stroke.
• Measure your sized brass and compare it to the fired brass. We recommend reducing the headspace of the fired brass by .001”-.003” for most shooting applications.
• To adjust sized brass headspace, thread the resizing die body in or out of the press as needed. We also recommend using Redding Competition Shell Holders. Alternatively, add or remove .001″ shims supplied with your die between the “Neck/Shoulder Bushing” and the “Taper Adapter”.

What’s in the Package

• Modular Sizing Die Body
• Standard orange or grey lock ring
• ER11 Top Cap
• Taper Adapter
• ER11 Collet
• Decapping Pin
• (4) .001″ Shims
• Cardboard Shipping box