Holosun 510C Spacer FDE Lower 1/3 Co-Witness, Flat Dark Earth

Holosun 510C Spacer FDE Features and Performance

The Holosun 510C Spacer FDE is a purpose-built lower 1/3 co-witness spacer for shooters who want their Holosun optic mounted cleanly, securely, and at the right height. Instead of forcing a generic plate or mount into the setup, this accessory is shaped around Holosun HS510C optics and QD mount assemblies, giving the optic a more dependable interface and a more finished installation. That matters when you are setting up a carry pistol, rifle, PCC, or range gun and want the sight to sit correctly from the start.

This mount or plate is built around precision-machined construction, corrosion-resistant finish, and a purpose-built fit for Holosun HS510C optics and QD mount assemblies. The result is a simple upgrade that helps reduce guesswork during installation. A proper adapter keeps the optic square to the mounting surface, supports repeatable alignment, and gives the rest of the firearm setup a cleaner, more professional feel. For pistol plates, the low-profile design helps maintain a natural sight picture. For rail mounts and spacers, the goal is better optic height and easier alignment with irons or magnifiers.

The Holosun 510C Spacer FDE is especially useful when you already know which optic and firearm combination you want to run. Its precision-machined aluminum body is made for regular range use, recoil, handling, and transport, while the Flat Dark Earth finish blends easily with common firearm builds. Small mounting parts are easy to overlook, but they often determine how comfortable the complete setup feels once the optic is installed.

Choose this lower 1/3 co-witness spacer when you want a cleaner Holosun installation without piecing together mismatched hardware. It keeps the optic setup focused, practical, and easy to understand, which is exactly what you want from a mounting accessory. For more optics, mounts, and firearm accessories, browse our accessories collection. For manufacturer information, visit Holosun’s official product resources.