The Mighty Armory Gold Match .300 Blackout Sizing Decapping Die is a Precision Match Series Die designed to restore fired brass to true SAAMI spec measurements from the case head to the neck. Size and decap .300 BLK cases in one step.
The Gold Match sizing die offers full-length headspace and concentric resizing back to SAAMI spec, easily adjustable with a simple turn of the die. Designed and machined for .300 BLK reloaders who demand reliable feeding in AR platforms, controlled headspace, uniform neck tension, and consistent chamber fit.
Full Length Sizing to SAAMI Spec
The .300 Blackout sizing die features an extended, full length sizing area that brings fired cases back to SAAMI measurements to prevent under-sizing or over-sizing at the neck, shoulder, and base.
SAAMI spec resizing results in:
- Proper and consistent case pressure
- Cleaner burning powder
- Reliable chambering and extraction
- Improved feeding reliability in AR platforms
- Longer brass life over multiple reloads
Full length sizing is recommended for all rifle cases, and is especially important for .300 BLK used in gas guns and suppressed setups. Neck sizing alone cannot correct base expansion or chamber-specific deformation and often leads to feeding issues and premature brass failure.
Precision Machined to Tight Tolerances
Mighty Armory Gold Match rifle sizing dies are precision machined from high-grade tool steel to tight tolerances to ensure consistent, uniform sizing and perfect vertical alignment. Our rifle reloading dies are single point cut finish with an extremely smooth sizing bore at 60 Rockwell hardness. A hard, smooth sizing surface that is consistent in sizing, especially head-spacing is of the utmost importance when reloading precision.
Drop-In Mandrel Expander Shaft
The .300 Blackout sizing die includes a Swiss-machined drop-in .300 BLK mandrel expander shaft, heat treated to 50 Rockwell for strength and durability. The mandrel expander shaft ensures uniform and consistent case mouth expansion for proper bullet seating.
The internal threads accept either:
- A Mighty Armory decapping pin, or
- A protective pointer that shields shaft threads and helps guide the case during sizing
The mandrel shaft sits concentrically inside the die bore with three points of contact (free bore, angle, and top flat). This modular design ensures positive lockup with the cap and consistent alignment through the sizing stroke.
One And Done Sizing And Decapping
The one-and-done sizing of your .300 Blackout brass will be effortless. Resize and decap your brass in a single stroke for efficient brass processing. The die will easily size over a million cycles.
Included features:
- Spring-loaded decapping system
- Two .078” diameter decapping pins included
The spring decapping action prevents primer pullback and helps reduce press chute jams on progressive presses.
Easily Adjust Shoulder Bump
Adjust the die in your press by turning it up or down to easily set shoulder bump from zero to -.005.
Resizing cases with the Mighty Armory Gold Match .300 Blackout Sizing Die will yield the precision you're looking for. Accurate sizing with Mighty Armory reloading dies enhances the safety, reliability and accuracy.
Key Benefits
- Full length sizing with shoulder bump up to -.005” The FLHS die head space bump is now standard on all Mighty Armory rifle sizing dies
- Restores brass to true SAAMI spec geometry
- 100% CNC machined, Made in the USA
- High-grade heat-treated tool steel
- Smooth 5 bore internal finish
- Concentricity to -.0005 at case mouth and shoulder radius
- Modular design, no tools required
- Built for precision reloading, high-volume use and long service life
Case Lube
For Single Stage or Turret Presses: We recommend a case sizing wax applied by your fingers.
For Progressive Presses: We recommend PEG75 lanolin spray.
For more detailed information about the Mighty Armory Gold Match Rifle Sizing Decapping Die, click the link and watch our video on YouTube!
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