Today, most new hunting rifles do not ship with iron sights. However, mounting a scope on a rifle is daunting if you have never done it before. Temptingly, many gun shops will offer to mount the scope on your rifle for you after the purchase. This is a bad idea! Usually, these mounting jobs will be out of level, not torqued to spec, or not set to the correct eye relief. Over the years I have seen way too many inaccurate rifles whose issues could be traced back to a store mounted optic. Here are the basics you need to properly mount your riflescope so that you be shooting your rifle instead of troubleshooting your rifle.
Tools
First off, let’s cover a few tools that are necessary to properly mount a scope. The most essential piece of equipment is a small torque screwdriver that measures in inch/lbs. These may seem expensive, but consider the cost of ammunition each time you unsuccessfully try to zero an optic or have an issue. Furthermore, improper torque can actually damage your scope. In today’s market where a box of ammo is $50 and a scope is many times that, the $100 for a torque screwdriver is a small price to pay. I’ve linked below the screwdriver I use personally. If you want to support the site consider using the button below. By clicking the link Northern Rifle gets a small percentage of the sale at no increased cost to you.
Another very useful tool is a small bubble level. Wheeler makes a set just for this purpose, but any 6 inch bubble level can do the trick with a little ingenuity. Finally, while not strictly necessary, a small tube of blue Loctite and a vise are also handy.
Process
Bases and Rings
First off, it is time to attach your bases to the rifle. Check the packaging or online to find the manufacturers recommended torque specifications for the base screws. For base screws, a small amount of Loctite helps to avoid backing them off. Using your torque screwdriver, tighten the screws to specifications. Make sure to carefully check and wipe off any excess Loctite that could work its way into the action.
Secondly, attach the rings to the bases. Following the steps above, Loctite the screws on the bottom of the rings and torque them to the manufacturer’s specifications.
Setting Eye Relief
Finally, it is time to put the scope in the rings and set the eye relief. Rest the scope in the rings and place the ringtops on top. Carefully adjust the tension on the ring screws so that the scope isn’t sliding around but you can still move it by hand without marring the finish. Do not use any Loctite on the ring screws. Loctite increases the torque slightly and too much torque can damage the tube of the scope.
Next, turn your scope up to the highest power setting and mount the rifle to your shoulder with your eyes closed. Open your eyes and see if you can see your reticle clearly without a dark ring around the edge of the glass. Repeat the process and incrementally slide the scope backwards or forwards as necessary until when you open your eyes the reticle is clear. Once you have the scope in the right position, you’re ready to level your scope to your action.
Leveling
The next step to mount a scope is to level the reticle. Take your new rifle and place it in your vice or on a rest. Use the bubble level to level the action. Sometimes it can be hard to find a flat spot-on certain actions. For most two-lug bolt action designs the raceways for the bolt lugs offer a good leveling point, and Wheeler makes a small level that fits into the raceway. I have also used the top of the action and the front sight base. Once your rifle is level put the level on the top of your scope turret and rotate the scope until the scope is level. If you have a capped turret remove the cap. The turret itself will be more consistently levelled to the reticle than the cap will be in most instances.
Another method for leveling a scope is to use a plumb bob and to level the rifle, then match the reticle in the scope to the string on the bob. This is the most accurate way to level a scope but getting the rifle pointed at the bob while keeping it perfectly level is challenging. As such, I typically opt for using bubble levels for both the rifle and the scope.
Finally, slowly tighten your ring screws a little bit at a time to the manufacturer’s specifications. For most scopes this is between 18 inch/lbs and 22 inch/lbs. Don’t worry if it doesn’t feel like it is enough torque. I have had scopes mounted at 18 inch/lbs stay put on a lightweight 338 Winchester Magnum for many rounds. Importantly, take care that your scope remains level while you tighten the screws on the rings. Having a scope that is not level can have a surprisingly significant impact for any kind of longer-range shooting.
Closing Thoughts
In closing, having an accurate rifle is all about eliminating variables that can introduce error. Many of these variables, such as changes in temperature, wind, and elevation we have little control over. In contrast, eradicating any possible errors from scope mounting is simple if you take a careful, meticulous approach. Additionally, mounting a scope right the first time avoids frustrating and expensive days at the range. Follow these steps and save yourself time, money and frustration the next time you buy a new hunting rifle.