Lee Undersize Sizing Die Only - Carbide .40sw/10mm*

The Lee Undersize Sizing Die Only - Carbide .40sw/10mm is a precision reloading component designed for handloaders who demand tight, consistent ammunition specifications. Built for both .40 S&W and 10mm platforms, this undersized die produces brass that chambers with minimal headspace variance, a critical requirement for match-grade loads and semi-automatic pistols with tighter tolerances. Whether you're loading for duty weapons, competitive shooting, or precision handgun work, undersized brass ensures reliable feeding and extraction across a range of firearm conditions.

This carbide die represents the premium standard in reloading die construction, eliminating the need for case lubrication and dramatically increasing production speed without sacrificing accuracy. Carbide dies feature a hardened, polished interior surface that resists wear far longer than conventional steel dies, maintaining dimensional consistency across thousands of reloading cycles. The undersize profile reduces case diameter slightly below SAAMI specifications, creating a measured squeeze that compresses the case shoulder and neck for enhanced cartridge uniformity—particularly valuable when working with once-fired or mixed-source brass that may have experienced slight expansion in various firearms.

Tactical shooters, law enforcement armorers, and serious competitors rely on undersized dies to achieve the tight case specifications that modern semi-automatic pistols require for reliability. This die pairs seamlessly with Lee's standard reloading press equipment and works with both .40 S&W and 10mm cases, making it ideal for shooters who load both calibers. At 0.45 lbs and compact dimensions, it integrates easily into any reloading setup while delivering the precision tolerances demanded by precision-focused handloaders.