Lyman MSR Precision Die System 458 SOCOM 4-Die Set

The Lyman MSR Precision Die System in 458 SOCOM is a purpose-built 4-die set from Lyman engineered specifically for reloading modern sporting rifle ammunition. Designed from the ground up for the MSR platform, this kit provides the dedicated tooling needed to produce reliable, accurate .458 SOCOM Bushmaster rounds for AR-platform semi-auto rifles.

The centerpiece of the set is a Small Base Sizing Die that sizes cases to a slightly smaller diameter than a standard sizing die, ensuring smooth and reliable chambering in semi-auto MSR actions. A separate Taper Crimp die is included to apply a proper crimp without distorting the bullet, and the full 4-die configuration completes the reloading process for this big-bore cartridge.

Every MSR Precision Die System also ships with an Ammo Checker cartridge "Go" gauge so reloaders can quickly verify that completed rounds will chamber properly in their rifle. All components are organized in a clear-cover storage case that keeps the dies protected, labeled, and ready for the bench. The Lyman 7690110 is the factory-engineered reloading solution for .458 SOCOM shooters running the AR platform.