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Picatinny Rail

The History of Picatinny Rail

When it comes to choosing a universal and reliable mounting solution, many of our customers pick the Picatinny rail as their preferred choice. This preference is not without good reason. The development of the Picatinny rail is an interesting story of innovation and standardization in the firearms industry.

Before the development of the Picatinny rail, the firearms industry faced a significant challenge: there was no real universal platform for attaching accessories to firearms. Although Weaver bases and rails were available, they did not offer a truly flexible or universal mounting solution. The need for a more versatile and standardized system led to the U.S. Army initiating a project in 1992 at the Picatinny Arsenal. Their goal was to create a mounting system that could easily accommodate a wide range of accessories, addressing the limitations of previous designs. This effort led to the creation of the first Picatinny rail, which has since become a standard in the industry, almost entirely replacing the Weaver.

Picatinny Arsenal, US

Figure 1: Picatinny Arsenal, US (Source: https://home.army.mil/picatinny/my-fort)

The project, which was led by the designer Gary Houtsma, involved analyzing and averaging different designs of Weaver rails. After numerous tests and refinements, the initiative led to the creation of a design that promised universality across various firearm accessories and manufacturers. The Picatinny rail, formally adopted in 1995, represented a significant step forward in the firearm accessory market. It was the first such system that provided a standardized platform that manufacturers across the industry could use, ensuring compatibility and increasing the range of accessory options. Interchangeability was another major driving force in the development of the new standard as different NATO armies needed to be compatible with each other.

Picatinny vs. STANAG 4694 NATO Rail

The STANAG 4694 NATO rail, introduced in 2009, serves as an update and partial replacement to the initial MIL-STD-1913 Picatinny design. This new standard shifts from the inch-based measurements of its predecessor to metric measurements. Another crucial improvement in STANAG 4694 is the introduction of angular tolerance for the rail's surfaces, specified at 45° +/- 20’, enhancing the alignment and precision compared to the MIL-STD-1913 where such tolerances were not defined. In terms of height, the MIL-STD-1913 had a larger tolerance range from the bottom contact points to the top face of the rail. STANAG 4694 reduces this tolerance, effectively halving it, which results in more accurate and consistent dimensions. Both the MIL-STD-1913 and STANAG 4694 maintain the same width for the outer edges of the rails. The STANAG standard evolved from four points of contact on the sides to bints of contact: two on the sides and one on the top.

Additionally, STANAG 4694 increases the clearance between the top surface of the rail and the bottom of the accessory base. This modification, along with the implementation of tighter tolerances and more controlled forms, aims to improve the secure attachment and reliability of mounted accessories.

General Description of Picatinny

In recent years, the trend of the Picatinny rail has become widespread and global, driven by the NATO standardized rails, more commonly known as the Picatinny rail standard.

The system quickly became an irreplaceable choice among users mostly for its universal and revolutionary design. The biggest and best advantage is that the Picatinny rail can be used along its entire length and is not limited to a few pre-designed slots, as was the case with the Weaver rail standard. The slots are placed 5.23 mm apart and are 3 mm deep. The widest part of the rail measures 21.2 mm across and shares this dimension with Weaver.

Another major advantage is the ease of use and interchangeability. If a product is designed for a Picatinny rail, it will fit all Picatinny rails, regardless of the manufacturer or date of production.

Contrary to the Weaver, which was most often available in the form of two-piece bases, the Picatinny rails are almost exclusively crafted from a single piece of metal or aluminum. In fact, some manufacturers like EGW or ERA-TAC have predominantly shifted towards using aluminum in recent years whereas some others like Rusan still primarily offer rails made of steel. It is generally considered wise to match the rail material with the material of the rifle’s mounting surface when installing a Picatinny.

Once installed, the axis of the Picatinny rail should be perfectly straight and aligned with the axis of the firearm, hence a rifle scope mounted in this configuration is also reliably aligned with the firearm and the ammunition’s trajectory.

Weaver rail design on the other hand is usually manufactured in two separate pieces, greatly increasing the possibilities for the axis to be crooked, overlapping, and out of line. When a single-piece Picatinny rail is used, the alignment process is simplified compared to using two separate mounting bases. With the use of one-piece Picatinny rails, the process of lapping, typically required for aligning two separate mounting rings, is generally no longer necessary. The single-piece rail will ensure that both rings are perfectly aligned with each other and that no unwished stress is transferred to the riflescope.

Weaver vs. Picatinny

The main difference between the Picatinny rail and the Weaver rail is the spacing of the slots. Contrary to Weaver, they are evenly spaced on Picatinny, each precisely 5.23 mm apart and 3 mm deep. This uniform spacing ensures consistent and repeatable mounting options across the board for different firearms that utilize the Picatinny rail standard. Depending on the rail's overall length, it also permits the horizontal adjustment of the mounting assembly along the surface, allowing for movement both forward and backwards.

In contrast, Weaver rail has 3.8 mm wide slots, which manufacturers can position anywhere on the rail in any desired number. The inconsistent spacing between the slots on different Weaver rails means that scopes with installed rings may not be easily transferable from one rail to another. While it is true that Picatinny rails are more advanced in comparison to Weaver ones, both mounting solutions are very reliable.

Are Weaver and Picatinny Mounts Interchangeable

Picatinny rail and Weaver rail share one more thing. It is possible to install the Weaver and the Picatinny mounts on the Picatinny rails, but it is impossible to use the Picatinny-suitable mounts on the Weaver bases. The reason is the above-mentioned positioning and spacing of the slots. Picatinny mounts have a 5 mm recoil stop that goes into the rail slot and since Weaver rail only has 3.8 mm wide slots such rings do not fit on Weaver rails.

Due to this reason, the Picatinny-rails are popular and prevailing on the market in recent years and eventually, these options will likely oust the Weaver rail from the market completely.

Advantages of Picatinny Rail

One big advantage of using the Picatinny rail over the Weaver rail is the consistent inclusion of the recoil stops. Furthermore, the manufacturing of the rail is not very technically demanding and can be done without the use of state-of-the-art machines, which greatly reduces the cost of the finished product, making it very affordable.

The Picatinny rail offers straightforward mounting and typically prevents the transmission of negative stresses and forces from the fired weapon to the riflescope. In addition, Picatinny with its very long useable surface works well for mounting longer rifle scopes or to achieve optimum eye relief. The durability and toughness are other big pluses for this solution.

Best Scope Mounts for Picatinny Rail

With the increasing popularity of Picatinny rails around the globe, the variety of manufacturers offering different scope mounts for the rail grew rapidly. Today, it is almost impossible for a manufacturer not to offer mounting systems for Picatinny standard. The rings that are attached to the rail can either be fixed or detachable-repeatable which means that the scope will retain zero even when removed and then reinstalled. The quickly detachable solutions are especially convenient for removing the scope from the weapon without the need for tools.

You can see our full offer of scope mounts that are suitable for Picatinny rail here:

Fixed Scope Mounts for Picatinny Rail

If you plan on using the same scope for longer periods on one rifle, then adding a fixed mounting system to your Picatinny might be the best possible solution for your needs. These steel 30 mm rings are manufactured by the Croatian company Rusan. They will fit both Weaver and Picatinny rails and come with a 10-year warranty.

Detachable Repeatable Scope Mounts for Picatinny Rail

This INNOMOUNT QD scope mount for Picatinny and Weaver rail is one of the most popular choices among our users when it comes to detachable repeatable systems. It is manufactured in Germany by the renowned company INNOMOUNT and is backed by a 10-year warranty.

Help Us Build Our Riflescope Mounts Database

If you happen to own this or any other rifle, we would appreciate it if you could help us expand our database by sending us some photos of the rifle receiver (the bare mounting surface of the rifle without the scope mounts installed). For your help, our company offers a fair return in terms of practical rewards.

Please send us an email for more information. You can contact us here: info@optics-trade.eu

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Risers are used to co-witness a red dot sight with iron sights of the firearm. You can have the sights aligned with the red dot (full co-witness) or at the bottom part of the optic’s field of view, with the dot above the sights (lower 1/3 co-witness).

Our customers are often confused by the terms adapter, riser, and spacer. These are used for the same purpose but have different mounting characteristics. The manufacturers of mounts are not consistent when it comes to naming these types of mounts.

For example, some mount manufacturers use the term ‘riser’ to refer to a mounting part that is referred to as ‘spacer’ by other mount manufacturers. Furthermore, some companies use the terms ‘riser’ and ‘spacer’ to describe a mounting item that is referred to as an adapter by other companies.

To eliminate confusion, we have relied on our own explanation when categorizing adapters, risers, and spacers.

These are the conditions that must be fulfilled for us to categorize a mount as a riser:

  • The mounting standard on the bottom and the top is the same. For example, it attaches to a Picatinny rail and has a Picatinny mounting surface on top.

  • It is always fixed to the mounting item below it, either with tools or through a quick-detachable method.

Red dot sight risers are almost exclusively made from aluminium.

They are produced by:

  1. American Defense,

  2. UTG, and many others.