For High Power shooters switching from iron sights to scopes (and who isn’t?), Leupold has a one-piece mount with integral rings tailored specifically for the flat-top AR-15 Service Rifle. The cantilever design accommodates pretty much any scope eligible for competition, and five screws clamp the mount to a Picatinny rail with unmatched tenacity—especially if you crank ‘em down to Leupold specs.
Leupold’s Integral Mount System (IMS) Mark AR one-piece mount is a single piece of machined matte black aluminum, with ring diameter to fit 30 mm or one-inch scope tubes. Overall length of the entire unit is right at 5½ inches; ring centers are 4⅛ inch apart, and the mount base measures 3⅝ inch in length. The distance between the rings, combined with the cantilever design, means probably any scope that meets NRA High Power rules will mount with proper eye relief.
Three lugs that serve as locking bars are machined into the base underside and engage three slots of the rifle’s Picatinny rail, while five keeper screws (yes, five!) clamp the base to the rail. Mount base keeper screws are a large Torx size T-27. The left side of the mount base is “blind” so that the ends of the keeper screws do not protrude, rendering a bit of streamlined appearance and providing a place to emblazon the Leupold name and logo. Four hollows machined into the base underside shave a little weight from the unit without sacrificing strength.
The solid mount and ring system raises the bottom of the scope tube 0.837 inch from the top of the Picatinny rail, which equates roughly to using medium-height rings clamped directly to the rail. Given that NRA High Power rules limit objective lens diameter to 34 mm, that should suffice for any eligible scope to clear the rail. It’s also low enough—putting the center of the ocular lens about 1½ inches above the Picatinny rail—for most shooters to maintain a good cheek weld when sighting. Ring screws, four to each ring, are Torx size T-15. The octagonal shape and the thinness of the ring upper halves aid the shooter in readily seeing the markings on the scope elevation turret.
Leupold’s accompanying instructions spell out a specific pattern for tightening the base keeper screws, rather like tightening head bolts on a car engine, and directs torquing the keeper screws to 65 inch-pounds and the ring screws to 28 inch-pounds. Yes, that sounds like a lot of torque for steel screws and aluminum mounts and rings when we consider that torquing aluminum rings to a mount with 25 inch-pounds maximum is the general recommendation, and for ring screws that number is 14-20 inch-pounds. However, proper torque is a function of, not just the metals involved, but also the screw diameter and thread pitch. Leupold’s beefy Mark AR mount keeper screws are threaded full length, and so are the screw holes in the base. This provides far more thread contact than other mounts with keeper screws that have only a few threads on the end of a smooth shank. This is why Leupold can recommend high torque value for the keeper screws.
After attaching the mount to my Service Rifle, I checked the alignment of the two rings with a pair of ring alignment bars. As the accompanying photo shows, alignment is perfect enough to melt the heart of the iciest critic. I mounted, appropriately enough, Leupold’s new Mark 4HD 1-4.5X 24 mm M1C3 SFP HPR-1 High Power competition scope for an evaluation in the June 2024 issue of the Shooting Sports USA digital magazine. Here, I’ll note that I’m happy enough with the Mark AR mount that another may find a home on one of my long-range .22s.
Leupold’s Integral Mount System (IMS) Mark AR one-piece mount is available at the Leupold website for $119.99, an excellent price for its quality and the confidence it offers.
Leupold also makes non-cantilevered IMS mounts for scopes with tubes of 34 mm and 35 mm diameter; these are suitable for bolt-action rifles with Picatinny rails, as well, and are advertised on Leupold’s website for $399.99.
Learn more at leupold.com.
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