Leupold Mark 4 Tactical Mounting Rings and Bases are engineered to be as rugged and reliable as the Leupold scopes they’re intended to secure. We’ve also created mounts for nearly every tactical rifle available, from bolt-actions to semi-auto rifles, and for every mission profile. No matter which Leupold tactical mount you choose, you can count on it to deliver rock-solid dependability and tack-driving repeatable accuracy.

Mark 4 8-40 Adaptable Mount:
Large caliber rifles are becoming more and more popular with today’s shooters. Mounting large riflescopes on these firearms with conventional 6-48 screws is not ideal, as the increased recoil and scope weight can over stress screws and lead to possible failures. More rugged, 8-40 screws increase mount strength by 41 percent, and are fast becoming necessary equipment on larger caliber rifles. Leupold’s Mark 4 8-40 Adaptable Mount is the first mount that can accommodate both the beefy 8-40 screw and a modified 6-48 shoulder screw. This mounting system features larger through holes that accept the thicker 8-40 screw, and the standard 6 48 screw has been replaced by a shoulder screw to work with the larger opening. This will give 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.

MARK 4 8-40 Adaptable Mount Features:

• Accepts both 6-48 shoulder screws and 8-40 screws
  
• Both 6-48 shoulder screws and 8-40 screws are included (6-48 shoulder screws are stronger than standard 6-48 screws; 8-40 screws are 41 percent stronger than standard 6-48 screws)
  
• These bases will fit Winchester PBR, Remington Super Magnum, HS Precision, and other 8-40 rifles without modification (some firearms will not work with these adaptable mounts – check current offerings for details)