RCBS 11131 Small Base Sizer Die .223 Remington Group A Reloading

The RCBS 11131 Small Base Sizer Die delivers precision resizing for .223 Remington cases fired in semi-automatic rifles. This specialized die reduces case dimensions beyond standard full-length sizing to ensure reliable chambering in tight-tolerance firearms.

What Makes This Different

Small base dies resize brass to smaller dimensions than standard full-length dies, addressing the expansion that occurs when cases are fired in gas-operated rifles. The reduced base diameter eliminates extraction and chambering issues common with standard dies. RCBS constructs these dies from hardened steel with precise tolerances to maintain consistent case dimensions shot after shot.

Key Features

• Small base design reduces case diameter 0.001-0.002 inches below standard sizing
• Hardened steel construction with precision-ground interior surfaces
• Group A classification fits standard 7/8-14 thread reloading presses
• Includes expander ball and decapping pin assembly
• Compatible with all major single-stage and progressive presses
• Vented design prevents case mouth damage during sizing
• Lifetime warranty against manufacturing defects

This die excels in high-volume reloading scenarios where cases have been fired multiple times in AR-15 platforms or other semi-automatic rifles. The small base sizing ensures consistent chambering across different firearms, reducing the risk of extraction failures during rapid fire sequences. Cases sized with this die maintain proper headspace while achieving the dimensional consistency required for match-grade ammunition.

Technical Specs

• Caliber: .223 Remington/5.56 NATO
• Thread: 7/8-14 TPI standard
• Material: Heat-treated alloy steel
• Finish: Black oxide coating
• Includes: Sizer die, expander ball, decapping pin
• Compatible with: All standard reloading presses
• Country of Origin: United States
• Warranty: Lifetime manufacturer warranty

Reloaders working with brass fired in semi-automatic platforms will find this die essential for maintaining reliable function. The precision manufacturing ensures consistent results across thousands of reloading cycles, making it a worthwhile investment for serious shooters.