C&H PLT ECHLN TO HOLO 407K/507K

Description

The Springfield Armory Echelon ships with a direct-mount optic cut that accepts several footprints, but the Holosun 407K and 507K use a proprietary mounting pattern that does not drop straight into that cut. This adapter plate from C&H Precision closes that gap, sitting between the slide and the optic to give either Holosun a solid, repeatable seat without requiring slide milling.

The plate is machined from aluminum and finished in MIL-SPEC Type III hard anodize. Type III hard anodize is a thicker, denser process than standard anodize, which matters here because the plate lives in a high-wear interface — clamped against a steel slide on one side and an optic base on the other, with every round generating a brief shock through that stack. The finish resists abrasion at those contact surfaces rather than just providing color.

All mounting hardware included is stainless steel, which avoids the corrosion mismatch you can get when carbon steel fasteners sit against aluminum under repeated wet or sweaty conditions. Three optic screws are included alongside the plate itself, so nothing additional needs to be sourced before installation. C&H recommends a dry-fit before final torque to account for tolerance variation across individual slides, optics, and plates — worth doing before applying thread locker.

Because the plate adds height to the optic mounting position, co-witness sight height with existing iron sights should be confirmed before committing to a final setup. The plate is designed specifically for the Echelon slide cut, so fitment with other Springfield models is not implied.