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What Size Scope Rings Do I Need: A Beginner’s Guide

1_What Size Scope Rings Do I Need

If you’re a new shooter trying to use scope rings on your firearms, you may be confused with all the different sizes and types available.

So, what size do you really need?

Fear not, as we are here to help you figure out the right size for your scope ring!

What Are Scope Rings?

Scope rings

These types of rings are used to hold the scope in place on the rifle. The ring mounts themselves are held onto the rifle using a scope base.

There are many different bases.

When talking about bases, the base you get should be from the SAME manufacturer.

Types of Rifle Scope Rings

Man shooting

Before finding the right size, we must first understand the different types of rifle scope ring and base.

Weaver Style

Probably the most common type of mounting system out there, the weaver-style mounting system uses a flat ⅞-inch broad base with crosswise recoil slots. 

The recoil slots on the Weaver base are .180 inches wide and are made to perfectly fit Weaver rings with the appropriate recoil lugs.

This lets it slots together like a jigsaw puzzle that doesn’t move from recoil!

These bases are made of aluminum or steel and can come in one or two pieces. This allows the shooter to swap scopes or remove them for maintenance or travel.

There are also some Weaver bases explicitly made for certain guns.

An example would be the Weaver style one-piece aluminum base explicitly made for the Remington 700. 


Picatinny rings are very similar to Weaver rings.

The main difference between them is that the recoil slots and recoil lugs on Picatinny bases are thicker than the recoil lugs and slots on a Weaver-style base.

Specifically, the recoil lugs and slots on Picatinny rings and bases are .206″ wide, while the recoil lugs and slots on Weaver style rings and bases are .180″ wide. 

Thus, Weaver-style rings CAN fit in Picatinny bases, but not so much the other way around.

Additionally, a Picatinny rail allows for multiple optics to be fitted evenly along the top of the rifle.

Leupold Style

This style is drastically different from the two abovementioned styles.

Leupold-style plates are usually made of steel and are available as either one or two pieces.

A caveat of this style is that it can be difficult to detach. 

Since the halves of the rings are loosely assembled, you will need a screwdriver handle or a one-inch wooden pole to gain leverage to turn them into the base.

To detach Leupold rings, you need to separate the top half.

.22 and 3/8″ Dovetail

Dovetail rings are commonly used in grooved receivers found on .22 rifles or airguns. These receivers consist of cuts that run lengthwise across the top of the gun. 

These cuts on the receiver are deep enough for dovetail rings to have a firm grip. If the metal on the receiver is not thick enough for the grooves, a ⅜” base is screwed onto the receiver.

⅜” dovetail rings come in various sizes that can hold scopes with main tubes of one inch, ¾,” ⅞,” etc. 

Some standard .22 rings are called a “one inch ⅜” dovetail ring” or a “one-inch tip-off.”

The great thing about dovetail rings is that they are fairly EASY to install at home! Some drove receivers are already drilled and tapped for use with Weaver-style bases.

These are ideal for when your rifle is designed for a broad base, as the riflescope rings will have more area to grab.

Extension Rings

There are many different rings and designs for extension rings. Additionally, extension rings allow for a shorter mounting distance on a longer receiver.

How to Choose the Right Scope Ring Size

Man shooting


The size you need depends on your rifle size and model. There are two things to keep in mind when looking for the right size.

Ring Width

The ring width should match the diameter of the scope’s main tube.

There are, in general, three sizes for the diameter of the tube:

  • 1 inch
  • 30 mm
  • 34 mm

If the ring doesn’t measure the same as the scope’s diameter, it simply will not fit.

Ring Height

Your scope’s ring height refers to how far above the bore the ring must be mounted for the firearm and optic to work properly.

Ideally, you’ll want the ring to be as CLOSE to the bore as possible. The closer the ring is to the bore, the fewer adjustments that have to be made.

However, it should still be far enough for the firearm to work properly.

To be able to measure what height you need, here are some measurements you will need to get (measuring all in inches):

  • Rail height: height measured from the top of the barrel to the top of the base/rail
  • Ring height: height measured from centerline of scope ring to top of the rail
  • Bell diameter of riflescope

Once you have all these measurements, you can then use the following formula:

(rail height + ring height) – (bell diameter x 0.5) = ideal ring height

Let us put this into an example.

If you have a 50mm riflescope with a 30mm tube length, the ideal height would be around 0.3 inches.

Take note that this computation may vary slightly depending on other factors.

How to Install Scope Rings

Man reloading

Be sure you have all the tools you need before starting, so you don’t waste time hunting down the things you need.

The best thing to use for screwing your rings in is usually a Torx head tool.

MOST IMPORTANT OF ALL: Be sure that the gun is UNLOADED. 

Also, ensure that your mounting system is CONSISTENT and that the base and ring match. A Leupold base, for example, will not fit with Talley rings. 

If you have dovetail receiver cuts on your rifle, be sure to use dovetail rings.

To make things a lot easier, use a gun rest or vise that protects the stock and fore-end to hold it securely in place.

Before you mount, check for any plugs in the base holes. Be sure as well that you are on a stable surface, such as a good solid table.

Installation Steps to Follow

Woman shooting

Now that we’ve got all that out of the way let’s move on to installing them! Most come divided into two halves: HORIZONTALLY and VERTICALLY.

For those that are divided horizontally:

  1. Start by positioning the lower portion of both the front and rear rings. Be sure to take your time with this step to ensure they are in the right position. 
  2. When you are sure of their position, tighten them with even screw pressure. 
  3. Lay the scope down onto the bottom halves of the rings.
  4. Carefully mount the top halves.
  5. Tighten the screws holding down the two rings to keep the scope in position. 

For those that are divided vertically:

  1. Place the scope in between the two ring halves.
  2. Secure the two halves using even pressure on the screws.
  3. Attach it to the base and lock it into place. 

Once you’ve successfully mounted your scope, check to see if it can be used properly.

  • Do you see shadows in the sight picture?
  • Do you need to move your head back and forth too much just to get a clear sight picture?
  • Did you lean so far back that your head lifted off the stock?

If so, you may have to move it forwards or backwards in the rings.

Once you’re sure of the scope’s distance, check if the reticles are on straight. Do you have to move the gun unnecessarily just for everything to be aligned?

If so, return the gun to the vise and carefully rotate the scope in its rings.

Keep making careful adjustments until you’re satisfied.

Remember that if anything is unsteady, it may affect your precision and thus result in a less than accurate shot. This can really affect your success when hunting!

Frequently Asked Questions

Are These Rings Necessary?

Yes, they are necessary for the shooter to be able to use the scope on their firearm.

Can You Use 30mm Rings on 1-Inch Scope?

It is possible to use 30mm rings on a 1-inch scope with the help of spacers. However, you CANNOT use 1-inch rings on a 30mm scope.

What Does 40mm Mean on a Rifle Scope?

40mm on a riflescope refers to its objective lens diameter. The larger the objective lens is, the MORE LIGHT can pass through, and the brighter the image.

Does a 30mm Rifle Scope Gather More Light?

Yes, a 30mm scope can gather slightly more light than a 1-inch one for better light transmission and low light performance.

Based solely on lens size, however, these differences are very minimal.

How Much Force Should Be Used When Installing the Rings?

It all depends.

Different rings and different manufacturers have different recommendations on how much force to use during installment.

Final Thoughts

Close up of optic

Don’t be afraid to try out different styles and manufacturers of scope rings!

We hope that the information we have given you helps you find the perfect mounting system for the perfect riflescope.

We hope that this means… the PERFECT shot!

Happy hunting!

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