One of the most common questions customers have after purchasing a Mosin Nagant is, “How do I mount a scope on there without altering my receiver?” Generally, scopes are installed on to a receiver that is drilled and tapped to take scope rings. This presents a problem on the Mosin Nagant, as the straight handle bolt would interfere with the scope’s eye piece. The only viable alternative is to install a scout style scope, but the wooden stock and fore grip of the Mosin make such a proposition a bit complicated to properly execute. S&K Manufacturing stepped up to the plate with its Mosin 91/30 scope mount. It utilizes existing hardware on the rifle and replaces the original iron sight with a Picatinny-style rail to which virtually any scout style scope can be attached.
The most difficult part of installing the scope mount is driving out the pin that holds the rear sight in place. You’ll need a few simple and inexpensive tools that aren’t included with the scope mount to accomplish this: a punch and a brass hammer. If you use a steel punch (which we recommend, as brass punches are too soft and may bend or break) be very careful to make sure that it is perfectly lined up with the pin before striking it so as to avoid marring the sight. On most Mosin Nagant rifles, this pin is held very tightly in place and takes a while to carefully drive out.
Once the pin is most of the way out, the spring pressure on the leaf sight will push the sight up and partially trap your punch. Carefully remove the punch and then the leaf sight and spring before continuing to drive the pin out. With the pin completely driven out and the spring and leaf sight removed, carefully place the flange nut into the rear of the sight holder. Placed properly, it should appear as shown in the image to the right.
Next, place the actual rail in place into the sight box and place one of the screws through the hole where the pin once was and gently thread it into place but do not tighten it. Using your punch, ensure that the flange nut is lined up with the countersunk hole in the top of the rail and then screw it into place with the countersunk screw and an Allen wrench until it is just snug and then loosen it 1/4-turn. Then, turn the screw through the other side of the pin hole until both sides are snug before backing out 1/4-turn.
At this point the rail should have some play and be able to be wiggled ever so slightly. Remove the bolt and place your scope on the rifle and gently snug the rail mount rings onto your rail. Bore sight the rifle by and adjust the set screws on the rail until the scope’s cross hairs are near the center of the bore. For this process, you may need to remove the scope, adjust the set screws and then place the scope back on the rail. Once you have a decent bore sight, tighten up the counter sunk screw into the flange nut and then the pivot screws where the pin used to be. With the rail tightened up, reinstall your scope and continue to sight it in as you would normally.