Leopold MARK 4 8-40 Adaptable Mounts - Leupold_s Mark 4 8-40 Adaptable Mount is the first mount that can accommodate both the 8-40 screw and a modified 6-48 shoulder screw. Larger through holes accept the thicker 8-40 screw increasing mount strength by 41 percent while the standard 6-48 screw has been replaced by a shoulder screw to work with the larger opening. This gives you the flexibility to mount your rifle with the common 6-48 screw size or drill and tap your gun to accept the 8-40 screws.
BASES Available for virtually every long-range tactical rifle Mark 4 bases accept Mark 4 rings cross-slot and QRW/PRW rings. One-piece bases have a 20 MOA slope for long-range shooting applications.
RINGS Available in machined aircraft-grade aluminum or StrikeForged steel options Mark 4 rings can be installed on any AR/ MSR platform or any firearm with a Picatinny-style base. They_re strong lightweight and exceptionally durable.