The most menial-looking components in a setup can sometimes be of extreme importance for the overall performance.
Scope mounts are a piece of equipment that fits true to this fact. With their importance mostly observed by pro shooters.
This article will cover in detail, the ins and out’s of scope mounts. So you’ll walk away with all the knowledge you need or may need on the topic.
Scope Mount Terminology and Common Concepts
It is important to get familiar with some technical and non-technical terms to get a better understanding of the topic.
Weaver Rail
The weaver rail is a flat rail setup that was founded in 1930 by William Ralph Weaver. These rails have horizontal slots with a width of 0.180 inches or 4.57mm. However, the spacing of slot centers is not consistent. This is a very common rail setup historically and is still prevalent to some extent today.
Picatinny Rail
Similar to the weaver setup, the Picatinny rail setup was developed in the 1990s. Also known as the MIL-STD-1913 rail, this is the standard rail setup of the U.S Military. The slots have a width of 0.206 inches or 5.03mm and a consistent gap of 0.394 inches or 10.1mm between slot centers.
This can be seen as an advanced and refined version of the weaver rail setup. Weaver devices will fit on Picatinny rails. Whereas the reverse is not always possible.
Dovetail Rail
Mostly found on rimfire rifles and air rifles. A dovetail rail is a 9 to 11mm wide piece of raised metal that has an inverted trapezoid shape. These rails are pre-built onto the receiver of a rifle and do not require you to add any extra adapter for adding scope mounts.
Objective Bell
Objective refers to the front face of an optic scope from where the light enters. The area around this region is called the objective bell and denotes the diameter of this part of the scope. This helps determine the clearance needed for mounting the scope on the rifle.
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Tube Size
The middle portion of an optic scope tube where the mounts grip the scope. The diameter of this tube is called the tube size. The most common tube sizes are 1 inch (25.4mm), 30mm, and 34mm.
Mount Height
The gap between the point where the mount is clamped to the rifle and the base of the scope ring is called the mount height. Scope mounts come in low, medium, and high rise variants for height. The choice of height depends upon the objective bell size, bolt lift angle, and a few other factors.
Integral Mount
These scope mounts are a single piece setup that includes the rings and mounting base as one unit. So you do not have to install a base or adapter first and then the rings. These help with quickly switching scopes on a rifle.
Quick Attach/Detach Mount
These types of scope mounts have a lever or knob arrangement on the side that allows you to quickly attach/detach them. Mostly without needing any tools.
Bolt Lift Angle
This is the angle at which the bolt in a bolt-action rifle has to be lifted to cycle the action. Bolts with full 90-degree lift angles can collide with the scope in some rifles. Hence requiring the adjustment of mount position or height.
Eye Relief
The gap between your eye and the scope eyepiece at which you can comfortably see your target. It can be fixed or variable.
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Cheek Weld
This refers to the position of your cheek on your rifle’s stock. Some rifles have an adjustable cheek weld. Making positioning of the eye more comfortable with scopes.
Flat Top or Round Top
Some scope rings come with a small piece of weaver/Picatinny rail built on their head to accommodate extra optics or accessories. Whereas most have normal round tops.
Ring Space
The distance between the rings on a single piece (cantilever) scope mount. While most scopes fit here, some may not.
Types of Scope Mounts
Scope mounts come in a wide variety of designs. Each of them has its own benefits which will be discussed further in the article. But first, make yourself familiar with these varieties.
Each of these mounts can either be a weaver, Picatinny, or dovetail scope mount. Except for an exception called the Leupold scope mount. The mounts designed for rail setups have recoil lugs in their bases that fit like a jigsaw into the rail slots.
Single Piece Mounts (Cantilever Mounts)
As the name suggests, these mounts feature a single piece construction that attaches to the base. These mounts are considered a bit more stable because the rings are pre-aligned and do not sway away even under pressure.
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An advanced version of these mounts has adjustable properties to set the windage and elevation as the shooting requirements (mostly range) change.
Two Piece Mounts (Scope Rings)
This is a two-piece setup that includes two scope rings with a base that is suitable for a weaver, Picatinny, or dovetail rail.
These are among the most commonly used mounts on bolt-action rifles. Especially on long range shooting rigs.
Integral Mounts
This is a simpler solution that houses the scope mount and the base in one unit so you can install it directly over the rifle’s receiver. Without having to buy the base and the scope mounts separately. Switching these types of mounts is time-consuming. But on the contrary, it is a more stable setup.
Offset Mount
An offset mount positions the scope slightly forwards, backward, or sideways than the position of the base. This helps get more rail space, especially when any other optics are being used in conjunction with the scope.
20 MOA Mount
These mounts are rails that are slightly angled and help the shooter increase the maximum adjustment range for elevation on their scope. This mount itself is a very detailed topic for discussion and is used very rarely for extra and ultra long range shooting. If you aren’t a pro sniper, you should probably leave this topic untouched.
Leupold Scope Mount
It is a standard non-weaver style mounting system and also one of the oldest setups. These mounts are designed to fit individual rifles. The front ring twist-locks into the base and the rear ring can be adjusted laterally to offer more refinement. This mount setup is preferred by hunters and also long range shooters.
Co-witness Mount
Any type of scope mount that allows the shooter to also use the iron sights with the scope is called a co-witness mount. However, The vertical level of alignment may differ from design to design.
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Pros and Cons of Single Piece Mounts
Single piece mounts are a hassle-free setup that is easy to install and widely preferred by short range shooters. Especially with assault and modern sporting rifles.
Pros of Single Piece Mounts
Some of the benefits of single piece mounts include:
Rigid and Strong
Single piece mounts are made from a single unit of metal. This design set up is very durable and you do not have to make alignments. These mounts usually have four or more screws that hold the setup together. Making factors like recoil and rough handling more negligible for disturbances.
Easy to Switch
A one-piece setup doesn’t need alignment and can be removed from the scope as a single unit. You can also carry the scope attached to the mount. Some models come with a quick attach/detach base. Hence making switching easier.
Adjustable Variations
Some single piece scope mounts have knobs that allow you to adjust for windage and elevation. Hence these also work as a 20 MOA mount.
Cons of Single Piece Mounts
Heavier and Pricey
These mounts have both rings connected with a long metal base. Which adds to the overall weight. Hence making them heavier than two piece setups. Due to these extra design features, these mounts tend to be more expensive than most other designs as well.
Limited in Application
Single piece mounts make cleaning the rifle cumbersome and have to be dismounted. Additionally, these mounts are not the best for bolt action rifles since they may interfere with the ejection slot.
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Pros and Cons of Two Piece Rings
Two piece rings, as the name suggests, is a combination of two metal rings that are separated in semi-circles along the horizontal or vertical axis.
Pros of Two Piece Rings
Suit Most Firearms
Since these are two individual rings that can be positioned anywhere along the rail base. Two piece rings suit most firearms and allows you to make the most out of your rail space. Whether the rifle is a long action, long barrel, or short action short barrel. These rings are not rigid in terms of rail space. Plus, they also don’t interfere with clearing and ejection on rifles.
Suit Most Scopes
Another benefit of having individually positioning rings is that you can use them with almost every scope having an appropriate tube diameter. Some scope rings also come with ring spacers to suit two tube diameters.
Affordable and Lightweight
These rings are often very inexpensive due to the low amount of material and complexity involved in their construction.
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Plus, these reduce the overall weight of the setup. Especially when compared with single piece mounts.
Cons of Two Piece Rings
Tedious to Interchange
In case you want to switch the rings to a different rifle.
You’ll have to go through unscrewing a lot of screws and then positioning the rings on the new rifle unless you get the best alignment.
Pros and Cons of Weaver Mounts
Weaver mounts are the oldest rail-based system of mounting scopes on rifles. Their design was revolutionary at the time they were introduced and is still used with many rifles.
Pros of Weaver Mounts
Works with Picatinny Rails
One big advantage of these mounts is they work with Picatinny rail systems which are more widely used and standard rail systems on rifles these days. This means your weaver mounts will suit a lot of different rifles. Except for those having dovetails.
Offers Easy Mounting/Dismounting
Weaver mounts with quick detach functionality can be mounted or dismounted from the rifle in an instant. Additionally, long weaver rails offer a lot of fore and aft space to adjust the scope according to your requirements.
Strong and Inexpensive
These mounts are strong, lightweight, and very inexpensive. These can be mounted on a long rail or two weaver slots that hold the mount very firmly.
Cons of Weaver Mounts
Non-standardized Design
The spacing between the grooves on a weaver rail is not constant. This means that you cannot mount standard Picatinny mounts on a weaver rail. This can be a problem when switching scopes on different rifles.
Canting Problems
Weaver mounts are subject to a bit of canting because Weaver rails rely upon hex screws for locking the mount into place. Rather than locking bars. This may cause the scope assembly to cant a bit.
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Pros and Cons of Picatinny Mounts
The latest and most standardized version of scope mounts. Picatinny mounts are used by the Military and also by most civilian shooters for their versatility. These are an advanced version of Weaver rails.
Pros of Picatinny Mounts
Standardized Design and More Space
Picatinny rails feature a standard and uniform design with equal spacing between the recoil lugs. This means that you can easily position the scope through the rail and can also extend it by adding an extension attachment. Picatinny rails are found on most rifles these days. Which allows for better chances of interchangeability.
Better Stability
Since Picatinny mounts use locking bars to attach with the rail. The entire setup is very stable and also very resilient to cant. Even under stress or harsh maneuvers. The close and uniform recoil lug spacing delivers more even and precise adjustments.
Cons of Picatinny Mounts
Not Versatile
A Picatinny mount will work only with Picatinny rails. Neither weaver nor dovetail. This means that you can only use these mounts with rifles that have a Picatinny rail. While not a very big problem with Picatinny becoming the standard mounting mode these days. But still a gripe for some specific situations.
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Pros and Cons of Leupold Mounts
Leupold mounts are the oldest type of mounts used for attaching a scope to the rifle. These are also called Redfield style mounts.
Pros of Leupold Mounts
Very Stable and Adjustable
These mounts attach directly to the rifle’s receiver. These are very stable and the rear mount almost always has windage adjustments to further complement the internal settings of the rifle scope.
Low Profile Design
Leupold mounts have a very slim and low profile design that allows the scope to stay closer to the rifle. The lack of any rail setup between the gun and scope is the main reason for that.
Cons of Leupold Mounts
Prone to Canting
The front ring being able to rotate presents a minor problem of canting. Especially under the influence of recoil or external pressure. However, that’s not a common phenomenon with these mounts.
Time-consuming Installation
The Leupold style base simply has many moving parts which make installation time consuming and also makes it prone to major or minor adjustment issues during use.
Conclusion
Scope mounts are responsible for adding a scope to a rifle. These are available in many design variants with each of them having its own pros and cons.
The most standard and widely used setup these days is the Picatinny scope mount which is also the standard mounting system for the U.S Military.
Photo credit: thefirearmblog.com
People Also Ask
From minor factors like eye relief to more important matters like mount height and cant. Check out this short and to-the-point FAQ section that resolves some general queries about scope mounts.
Do I Need a Medium or High Scope Rings?
The closer the scope is to the rifle, the better. But, the size of the objective bell and the bolt lift angle will decide the height of the scope rings. The point is that the objective bell doesn’t touch the barrel and the cycling is not hindered. Go for high rings only when necessary.
How Much Space Should Be Between Scope and Barrel?
You can get as close as you like unless the scope doesn’t touch the barrel. So a minimum space of about 5mm can be considered suitable.
Does Scope Height Affect Accuracy?
The scope height will not play a very important part in accuracy if you take care of the scope cant when using high rings. Eventually, the goal is to make the point of aim and point of impact intersect. Higher scopes just require you to be more vigilant about some extra factors that come into play.
How Far Should The Scope Be From Your Eye?
This distance is called eye relief and there’s no hard and fast rule for that. It all depends upon your comfort level, magnification, and recoil of the rifle (so the eyepiece doesn’t dig back into your eye). Three to four inches is a good value.
