The Spuhr Interface

The Spuhr Interface is deliberately engineered to eliminate the weak points found in traditional accessory mounting systems. Instead of bolting accessories to long stretches of Picatinny rail, Spuhr machines a lightweight “male–female” interface into their mounts: the female side consists of a pair of M4‑threaded holes with dual conical surfaces, and the male side has matching cones. When the cones are mated, they create a solid, repeatable mechanical lock that carries all of the shear and torsional forces. The screws simply draw the cones together and keep them seated; they do not experience the bending stress that typical accessory screws see.

This geometry gives the interface remarkable strength and reliability – the accessory is held rattle‑free with a perfect fit, yet the design removes material so the interface actually reduces overall weight. Unlike KeyMod or M‑LOK, the Spuhr Interface doesn’t need extra clearance behind the attachment point, so it can be used on scope mounts, forends or even the side of a magwell. Spuhr offers a range of direct‑mount accessories for this interface – such as red‑dot bases and short Picatinny sections – that take advantage of the lower profile, lighter weight and higher strength compared with bolting through a rail