There are two methods of doing things in life: the wrong way and the right way. The right way often may take longer, but the results are almost always much better than the wrong way. This is especially true when it comes to the wonderful world of firearms and shooting. There certainly is a wrong vs. right way.
For the two decades I have been a firearms instructor, I have seen both the right way and the wrong way. The wrong way is certainly not pretty.
When it comes to properly mounting an optic on a firearm, I have seen many people get it oh-so-very wrong. I’ve seen optics fly off of rifles or take a pounding from rattling around loose mounts screwing up the zero. The wrong way can cost you a deer, a competition or even your life.
The right way can fill your freezer, win trophies and protect your life and that of your family. It only takes a little bit of time and perhaps a few extra dollars to do this the right way.
Let’s discuss the right way to mount an optic on your firearm.
You will need a stable rest for your rifle that keeps the firearm in a solid position; you can buy one or build one. Furthermore, you will need a good set of screwdrivers here, with some flatheads. I have yet to ever need a Phillip’s head to mount a scope. For the bases themselves, you will most likely need a larger head, while the rings will require a smaller head.
Having a scope level makes your job go by so much more easily. Most of these are magnetic and stick to the top of a scope’s turret. Don’t scrimp and neglect to purchase one of these, as they are not expensive and will save you time.
Mounting Your Optic
The first step is to have the rifle you want the optic mounted on to be drilled and tapped. Most modern firearms come drilled and tapped, or if you are shooting an AR-15 or anything in that class you will most likely have a Picatinny rail. After you have your ducks lined up in a row with your rifle, choose your optic. We’ll discuss optics another day, but I will say to be sure you also have the right screws, bases, rings, Allen wrenches, everything you need to mount your optic before you get to it. Double check your rings and mounts before you leave the store and make sure you have the right size.
Pay attention to your bases and mounting screws. This is especially important for a drilled and tapped rifle. You don’t want to widen out your tapped drill holes in the receiver of the firearm. You also don’t want to strip screws. Don’t settle for substandard parts or the wrong size screws and parts.
Thoroughly clean your firearm and you mounts. Be sure you get any grit and debris off of the area you will be mounting to, and from the scope’s bases. Taking your time here will prevent rust and scratches.
My next step here is to dab a thin layer of Hoppe’s 9 or a decent protective oil onto the receiver where you will be installing your new scope. If you have a Picatinny rail system and you need to install a riser mount to offset an AR-10 or AR-15’s front sight, do so at this time, and after that install the bases but wait to tighten in case you have last-minute adjustments. For a rifle with traditional taped receiver, install the base mounts and get the screws as tight as you can without stripping them.
Next, install the bottom rings and place the optic on them. Adjust to where you want the optic to be and then place the top rings on the scope. Use a good scope level and be sure everything is kosher. When you’ve done this, tighten everything up.
Be sure everything is secure, and give it all one last tightening.
When you are satisfied with your work, take your rifle out and sight her in. If you have done a good job, you should have no problem getting nice tight groups and maintaining the scope’s zero.
Before sighting in your rifle, I highly recommend you purchase a quality shooting rest such as a Lead Sled, or borrow one from a buddy. A laser bore sight is a great tool, as is a quality spotting optic.
I prefer to laser bore sight a rifle first. Place your bore sight in your firearm’s chamber and set up a target at 25 yards. Unscrew the turret caps that cover the adjustment knobs on your scope. The laser sight will make a laser dot appear on the target; adjust you optic until the cross hairs are right on your laser’s dot. This eliminates much of the time to get on target and should ensure your first rounds hit near the bullseye. You will probably have to tweak your adjustments slightly downrange, but this step saves ammo.
Next, set up a target at 100 yards. Shoot three rounds and group your rifle. Make any needed adjustments to your scope and shoot a few more rounds. Normally this step takes me around 3-10 rounds of ammunition. Keep in mind that most shooting optics have an adjustment of one-fourth MOA, meaning that every time you adjust your scope one click you are moving it a quarter of an inch or a one-half centimeter at 100 yards.
After you have sighted in your rifle, replace your scope’s turret caps and be sure that they are snug. You may need to readjust your scope after every few hundred rounds.
What advice would you add in mounting a scope? Share your thoughts in the section below: