Prepper's Armory: Scope Mounting

As with iron sights, there's a proper way to mount, adjust, and sight in a scope. Actually, I should say proper ways, because there are a number of variables as well as preferences involved with the process.

Early scopes were externally adjusted, meaning the scope body was solid and the adjustment knobs were located on the scope mounts. Turning these knobs physically changed the angle of the scope tube. Later, the adjustment knobs were moved to the scope body itself, making adjustments simpler. Further developments made the adjustments more consistent and predictable.

Components

The first steps in mounting a scope to a firearm is acquiring a solid rail mount and the proper rings.

Rail mounts come in one- and two-piece configurations and Weaver or Picatinny rail patterns. These days, one-piece Picatinny are the most common; in fact, many firearms come with Picatinny rail either built into the design, or supplied as an optional attachment. Despite the difference in their appearance, they are functionally identical. 

Weaver (L) and Picatinny (R) rail sections

Scope rings come in diameters for the two most common scope tube sizes, 1" and 30mm. The height of the rings is also important: ideally, the scope is mounted as low as possible but with some clearance between the objective lens and the barrel. If removable lens caps are to be used, their diameter should be taken into consideration when selecting scope ring height.

Mounting Process

If necessary, mount the rail to the firearm. A single drop of blue Loctite can be used to prevent the screws from backing out if they don't come with thread locker already applied. 

Next, attach the ring bases to the rail. Position them so that when the scope is in place they are relatively centered between the adjustment knobs and where the scope tube swells out at either end.

Once the rail and ring bases have been properly mounted to the rifle, place the scope on the rings and determine the best position for optimal eye relief. Keep in mind this can be adjusted in small increments once everything is in place, but try to get it as close as possible. (Proper eye relief is when the shooter can place their head in a comfortable position on the stock and still see the entire field of view through the scope without any fuzzing around the edges.)

Once scope position is determined, install the top half of the rings and loosely screw them down. Don't tighten them all the way yet; scope orientation needs to be checked and confirmed. This can be done by eye, but a better option is to use a leveling tool. Secure the firearm in a soft jaw vice and try to get it as level as possible first, then attach the scope leveling tool and rotate the scope until the reticle is level.

Scope Leveling Tool

When tightening the scope ring screws, be careful not to overtighten them. Most scope and scope ring manufactures recommend 25 inch-pounds as a maximum. While this can be done by feel, a safer and more precise option is using a torque wrench. This can either be a dedicated tool or an adapter for an existing bit driver.

The screws should also be tightened in a pattern to avoid applying too much pressure to one side and twisting the scope. Since most rings have four screws each, a figure eight pattern is recommended, tightening each screw partially in turn until they're all done. Make sure the reticle remains level throughout the process.

Sighting In

Once the scope is successfully mounted, it's ready to be sighted in, but that's a topic for another article.

Have fun, and safe shooting.