Choosing the right scope mounts, scope rings and mounting rails is essential for the compatibility, stability and accuracy of the entire setup. The scope tube diameter alone is not enough: you must also consider the rifle or air rifle, the mounting system, the mounting height and the type of optic.
In this guide, we explain how to choose the right mounts for hunting rifles, air rifles, PCP air rifles, riflescopes, red dot sights and thermal optics.
What you need to know before buying scope mounts
Before buying scope mounts or a set of scope rings, gather as much information as possible about the rifle and the optic. A mount may fit the scope but still be incompatible with the rifle or the existing rail.
- Exact make and model of the rifle or air rifle.
- Type and design of the firearm.
- Mounting rail already fitted.
- Diameter of the scope’s main tube.
- External diameter of the objective bell.
- Whether a detachable mount is required.
- Intended use: hunting, target shooting, air rifle, PCP, red dot sight or thermal optics.
If you have not chosen a riflescope yet, our guide to choosing a hunting scope may help.
1. Check the rifle make and model
The first check must be carried out on the rifle. Two models from the same manufacturer may use different mounting systems depending on the calibre, action, production year or configuration.
A mount designed for a particular receiver or action from Remington, Tikka, Mauser, Sauer, Blaser, Browning or Merkel is therefore not automatically universal. Important differences also exist between bolt-action rifles, semi-automatic rifles, rimfire rifles and air rifles.
Always record the manufacturer, exact model and, where applicable, the specific model variant. Depending on the mount, you may also need to know the calibre, action length or the design of the existing base.
2. Identify the mounting system
The mounting system fitted to the rifle determines which mount or base can be used.
- 11 mm dovetail rail: commonly found on air rifles and some rimfire rifles.
- Weaver rail: features cross-slots for the recoil lug of the mount.
- Picatinny rail: a standardised rail system with defined cross-slot dimensions.
- Model-specific base: designed for a particular rifle model or receiver.
- Integrated rail: found on certain rifles and riflescopes.
- Quick-detachable mount: allows the optic to be removed and reinstalled.
Weaver and Picatinny rails are similar, but they are not automatically identical. Always check the compatibility specified by the manufacturer.
For more information, read our guide on how to choose the right scope mount.
3. Choose the correct scope tube diameter
Scope rings clamp around the main tube of the riflescope. The internal diameter of the rings must therefore match the external diameter of the scope tube exactly.
| Scope tube diameter | Equivalent | Typical use |
|---|---|---|
| 1 inch | 25.4 mm | Classic riflescopes and many air rifle optics |
| 30 mm | 30 mm | Hunting and target-shooting riflescopes |
| 34 mm | 34 mm | Optics with a larger adjustment range |
| 35 and 36 mm | Manufacturer dependent | Specialist or tactical optics |
The objective bell diameter is not the same as the scope tube diameter. For example, a riflescope with a 50 mm objective may have a 30 mm or 34 mm main tube. Rings are selected according to the main tube, not the objective bell.
4. Determine the correct mounting height
The mounting height must provide enough clearance to prevent the objective bell from touching the barrel, receiver or other components. At the same time, the riflescope should be mounted as low as possible for a comfortable shooting position.
There is no universal mounting height for a particular objective diameter. The required height depends on several factors:
- The actual external diameter of the objective bell.
- The height of the base or mounting rail.
- The geometry of the receiver and barrel.
- The design of the mount.
- The use of scope caps or an objective protector.
- The stock design and the shooter’s natural head position.
The abbreviation BH may refer to the distance from the mounting surface to the centreline of the scope tube. Since manufacturers may use different measuring criteria, BH specifications should not be compared without checking how they were measured.
The final mounting height must always be checked on the complete system, including the rifle, base, rings and riflescope.
5. Zeiss and Swarovski integrated rails
Some riflescopes do not have a completely cylindrical main tube for conventional scope rings. Instead, they feature an integrated mounting rail on the underside, as found on certain Zeiss and Swarovski optics.
- Exact make and model of the riflescope.
- Type of integrated rail.
- Compatibility of the mount with that rail.
- Mounting system fitted to the rifle.
- Final mounting height and available space for accessories.
A mount designed for a Zeiss integrated rail must not automatically be replaced with a mount for a 30 mm tube. The contact surface and fastening system are different.
6. Fixed, detachable and one-piece mounts
Fixed mounts are suitable when the riflescope does not need to be removed regularly. They may consist of separate scope rings or a dedicated mounting system.
Detachable mounts allow the optic to be removed for using open sights, transport or changing the rifle configuration. Repeatability depends on the quality of the system and its installation.
One-piece mounts integrate the mounting points into a single component. They are frequently used on powerful air rifles and PCP air rifles.
Rings with a separate base provide a flexible solution because the base can be matched to the rifle and the rings to the scope tube diameter and mounting height.
You can also read our guide to fixed and detachable Warne mounts and our analysis of Leupold mounts.
7. 0 MOA and 20 MOA bases
A 0 MOA base does not add any significant inclination to the system. A 20 MOA base incorporates an inclination that can provide additional elevation adjustment range in certain long-range configurations.
The choice depends on the riflescope, shooting distance, ammunition, elevation adjustment range and rifle. A 20 MOA base is not automatically the better option for every application.
8. Compatibility with hunting, air rifle and PCP optics
The correct mount also depends on the optic and the type of firearm on which it will be installed.
- Hunting rifles: check the action, rifle model, scope tube diameter and whether a model-specific base is required.
- Air rifles: pay particular attention to the 11 mm rail, scope tube diameter and recoil resistance.
- PCP air rifles: check rail spacing, magazine clearance, objective bell and final mounting height.
- Red dot and thermal sights: check the footprint, weight, interface and resistance of the mounting system.
Discover our selection of hunting riflescopes, air rifle scopes and PCP air rifles.
Final checklist before buying
- Have you confirmed the exact make and model of the firearm?
- Does it use a dovetail, Weaver, Picatinny or model-specific base?
- Does the scope ring diameter match the main tube?
- Have you checked the external diameter of the objective bell?
- Have you checked the BH reference according to the manufacturer’s measuring criteria?
- Does the riflescope use a conventional tube or an integrated rail?
- Do you need a fixed, detachable or one-piece mount?
- Is a 0 MOA or 20 MOA base required?
- Can the mount support the weight and recoil of the configuration?
- Have you checked that the scope, objective bell, barrel, receiver and accessories do not touch?
How to mount a riflescope correctly
Before starting, make sure that the firearm is unloaded and in a safe condition. Clean the contact surfaces, set the correct eye relief and level the reticle before tightening the screws fully.
Always use the tightening torques specified by the manufacturer of the mount, scope rings and riflescope. A single universal torque value is not suitable for every screw or material.
For further information, read our guide on how to mount a riflescope correctly.
Find the right scope mounts and rings
In our scope mounts category, you will find scope rings, bases and mounting systems for rifles, air rifles and different types of optics.
