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How to Mount a Rifle Scope on a Picatinny Rail

Last Updated on June 10, 2021

scope ring

Mounting your rifle scope is one of the first steps in making the rifle yours. You may be asking why couldn’t the guys at the gun shop do it for you? Well, they could, but knowing how to do it yourself is going to save your time and you’ll learn more.

You will also be able to get familiar with your rifle and when it comes time to upgrade or get a new optic in the future, you will know how to remove it safely and attach a new one. Also, when it comes time to do some routine maintenance on your rifle, you’ll be able to do it yourself without having to go into a shop.

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What is a Picatinny Rail?

A picaninny rail is the most widely used rail for rifle shooting today. There are many models on the market right that that come with a pre-mounted Picatinny rail. The lighter weight of this rail keeps the weapon more agile, but it also saves you time fixing a mount to your rifle yourself.

Unlike the other mounts out there, this one has a wider and deeper slot. It is thicker than a two-piece mount due to it offering an ejection port relief. The spacing of this mount extends the full length of the mount, giving you more freedom to move your scope if need be to get the correct eye relief.

UTG MNTP503 Tactical Picatinny

Equipment You’ll Need

 Before you get started on mounting your scope to your picaninny rail, you are going to need a few tools to make the job not only smoother but doable.

  • Torque wrench: This will determine if you even mount your scope or not. This cannot be done without a torque wrench.
  • Tape: Not every user will want to use tape, have it on hand just in case to mark the bottom and top of your scope rings.
  • Leveling kit: Again, unnecessary but helpful in making sure your scope is level with your rifle. Also helpful if you switched scopes later on down the line.
  • Gun stabilizer: You could use a gun vice here, but just stabilizing your gun will also do the trick. Having a way to move around your gun without holding it is key.
  • Scope rings: You cannot mount your scope without proper fitting scope rings on the picaninny rail.

Mounting Your Scope

Once you have your gun stabilized and easy to work around, you can start with the mounting of your scope. This is going to happen in three stages: The placement stage, the adjustment stage, and the tightening stage.

Placement Stage

The very first stage is taking the scope rings that are the proper size for your scope and opening them. With various brands you are going to want to keep the top and bottom rings together. A way to do this is to mark the tops of the scope rings with a tape. Label them the way you see fit and set the tops aside.

Place the rings on the rail loosely. The placement for this is going to different depending on the scope you have. Check in with the user manual for the best placement of the rings on the rail. Keep the rings loose but not falling off as you may have to adjust the alignment with your scope later on.

BCM AR-15

Image Credit: BCM AR-15, Motohide Miwa, Wikimedia Commons CC 2.0

Adjustment Stage

Now it is time to place your scope on the rings. Make sure the scope sits currently and that your eye relief is in the right place. It is best to check with the manufacture or user manual of your scope to know the eye relief.

If your scope isn’t in the right spot, adjust the rings to where they should be to give you the best view possible. Adjust to the shape and size of your scope as well. The rings are meant to sit in a certain position in order to not only hold your scope but keep it in place with the recoil.

Once you’ve made your adjustments, make sure the rings are sitting correctly on the rail and that your scope is sitting snugly in the rings. Make sure the ridge of your ring first in the rail towards the forward. When the rifle recoils it goes towards the back, and you don’t want any shift in your scope towards your eye.

Tightening Stage

Once you have everything adjusted correctly, you can tighten the rings to the rail. You are going to use your torque wrench to do this step. Each rail and ring is going to be a little different, so check the manual for the correct amount. You don’t want to overdo it and risk cracking the ring.

Now that you have the bottom ring tightened, you need to match the upper ring. Since you labeled them, you can easily attach them to the correct ring. Once you have the rings loosely secured, get your scope level out. You’ll have to make a few adjustments as you go, tightening each screw on either side of the rings until the bubble is in the middle.

The last step is then to take your torque wrench and tighten the upper rings firmly.

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Mounting Your Scope

There you have it. Your scope is now mounted and secure. From here you’ll have to adjust the vision in your new scope to be perfect for you. After that, you’ll have to take it out and give a test run. Now you know how to mount your scope on a Picatinny rail.


Featured Image Credit: Nikon Buckmasters Rifle Scope 6-18x 40mm SF Mil-Dot mounted on a 24″ Rock River Arms Varmint A4, betancourt, Wikimedia Commons CC 2.0

About the Author Robert Sparks

Robert’s obsession with all things optical started early in life, when his optician father would bring home prototypes for Robert to play with. Nowadays, Robert is dedicated to helping others find the right optics for their needs. His hobbies include astronomy, astrophysics, and model building. Originally from Newark, NJ, he resides in Santa Fe, New Mexico, where the nighttime skies are filled with glittering stars.