SAC Modular Sizing Die – .300 Blaser Magnum

Our new Modular Sizing Dies support a family of cartridges. The Modular Sizing Die – 300 Blaser Magnum works with rifles chambered based on CIP 300 Blaser Magnum reamers. Each die includes one Neck/Shoulder Bushing of your choice. Be sure to select your preferred bushing from the menu before adding the die to your cart.

• The Modular Sizing Die for the 300 Blaser Magnum fits chambers based on CIP 300 Blaser Magnum.
• Our die sizes more at the base and less at the shoulder than traditional resizing dies. (If your chamber has excessive headspace or is oversized, expect increased sizing force or potential for stuck cases.)
• We use 17-4 H1150 Stainless steel and apply a nitride finish to maximize lubricity and durability.
• Made in the USA
• For questions about reamer compatibility, email us at info@shortactioncustoms.com.

The “Modular Sizing Die” uniquely sizes the cartridge’s body geometry with the die body, while a “Neck / Shoulder Bushing” handles the shoulder and neck geometry. This allows one die body to work for the entire cartridge family.

Our Modular Sizing Dies focus on properly sizing your fired brass. These dies size the cartridge base slightly more than the shoulder, enhancing performance.

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

We designed the cartridge sizing geometry to size slightly more at the base and slightly less at the shoulder compared to most resizing dies. For properly sized rifle chambers, this helps avoid extraction issues with fired brass and reduces case runout by minimizing over-sizing of the shoulder.

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 increased lubricity and performance.
• Universal Solid Decapping Pin: High-strength 1144 Stress Proof Steel, with a .058” pin tip diameter to fit small primer flash holes. Adjust the pin tip protrusion by positioning the wide-mouth retaining clip.
• Knurled ER11 Top Cap: ¾ x 24 Threads secure the Knurled ER11 Top Cap to the die body, compressing the ER11 collet to ensure the utmost concentricity for the Decapping Pin or Expander Mandrel.
• ER11 Collet: A commercially available ER11 collet secures various Decapping Pin and Expander Mandrel diameters.
• Taper Adapter: The Taper Adapter, seated above the Neck/Shoulder Sizing Bushing, holds the ER11 Collet and allows the Neck/Shoulder Sizing Bushing to float.
• Neck/Shoulder Bushings: Available in various caliber-specific neck diameters. You can add .001” shims above the Neck/Shoulder Bushing to adjust headspace without threading the die in or out.

Follow these steps to set up your Short Action Customs Modular Sizing Die

• Ensure the inside of the resizing die is clean and free of debris. We recommend using a .40 caliber plastic pistol brush with a 12-gauge shotgun patch to clean the inside of the die body.
• Assemble your Modular die as shown in the picture below.
• With the reloading press ram fully raised, thread the resizing die into the top of the reloading press until the die body touches the shell holder. Lower the ram slightly, then continue threading the die down to achieve a slight “cam over” with the press. Tighten the die body lock ring. For the Area 419 Zero Press, thread your die approximately 1/8″ turn after it touches the shell holder.
• Use a headspace comparator that contacts the shoulder of the brass to establish the fired brass headspace.
• Lubricate a piece of clean, fired brass and cycle it through the Modular Sizing die with a smooth, consistent ram stroke.
• Measure the sized brass and compare it to the fired brass. We recommend reducing the headspace of the fired brass by .001”-.003” for most applications.
• To adjust sized brass headspace, thread the resizing die body into the press more or less. We also recommend using Redding Competition Shell Holders. Alternatively, you can adjust headspace by adding or removing .001″ shims between the “Neck/Shoulder Bushing” and the “Taper Adapter”.

What’s in the package

• Modular Sizing Die Body
• Standard orange or grey Die lock ring
• ER11 Top Cap
• Taper Adapter
• ER11 Collet
• Decapping Pin
• (4) .001″ Shims
• (4) .025″ Shims
• Cardboard Shipping tube