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When you want to add a rifle scope, red dot sight, or other attachment to your weapon, you need a reliable accessory rail system to keep the component securely attached. The two most popular mounting systems are Picatinny rails and Weaver rails, and each one has specific advantages that could make it the right choice for your next build. Even though Weaver rails are an older scope mounting system, they still have their place in modern times, especially with certain firearms and Weaver accessories. On the other hand, Picatinny rails are more streamlined, as they were developed by the U.S. Military to be a standardized, updated version of the original Weaver design. If you're curious about how these rail systems differ and which one you should choose, this guide discusses their history, features, and drawbacks so that you can make an informed decision.
History of the Rail Systems
Let's start by talking about Weaver rails. Developed by William Ralph Weaver after he started W.R. Weaver Co. in 1930. He designed the rail system because he wanted a secure, tough way to mount his Weaver optics that he was creating. The original Weaver rail system used two separate pieces to provide the base for the rifle scopes. These were mounted apart from each other, usually over the bolt opening on the receiver. This was a pretty big step because it allowed his customers to mount rifle scopes easily without obstructing the bolt or ejection port.
While the Weaver rail was popular, the U.S. Army wanted a standardized version to use on their weapons, so they turned to Picatinny Arsenal in New Jersey. The engineering team was headed by Gary Houtsma, who started measuring rail systems on weapons and coming up with an average. When he took these findings to the engineering team, they noticed it was similar to the rails on a 105mm Howitzer, so they used this as a baseline. By scaling everything down, they came up with the Picatinny rail system, also known as Pic rails, in 1995, which is when it was adopted by the U.S. Military and given the designation MIL-STD-1913 rail.
Notable Features of Weaver & Picatinny Rails
Weaver rails were a big step forward for attaching rifle scopes, as they made the process more accessible. Since the original Weaver design was modified from a low dovetail rail, it was easy to install. Plus, using two separate pieces left space over the bolt, which meant they didn't obstruct the weapon. This was particularly useful because you could still load stripper clips and individual rounds. Each slot on Weaver rails had a width of 0.180 inches and was rounded, but the spacing between slots wasn't always consistent. While most rifle scopes and scope rings would work, they could cause confusion and compatibility issues. However, this wasn't a big deal, as it still made it easy for civilians to attach optics to hunting rifles and opened the door for more customization.
Even though Weaver rails were a huge step forward, the real renaissance of weapon accessories on rifles, carbines, shotguns, and even handguns came with the development of Picatinny mount rails. The main benefit of Picatinny rails is that they are standardized. Each locking slot is 0.206 inches wide, 0.118 deep, and has an exact spacing of 0.394 inches. The slots also have square bottoms, making them look clean and sleek. Since everything remains consistent and standard, manufacturers could run wild developing new weapon accessories that could conceivably fit on any weapon with a Picatinny rail. This led to the advancement of weapon-mounted Picatinny accessories, like laser sights, red dot sights, rifle scopes, foregrips, and many other common items today. Most modern weapons with mounting systems are made with installed Picatinny rails, or you can purchase and add them easily without gunsmithing equipment or experience.
And Now, the Drawbacks
No system is perfect, even if it is revolutionary or seems to be the best option available. Like before, we'll start with the Weaver system. Even though the two-piece design had its advantages, it also brought about a unique issue. When using two pieces to mount a rifle scope, you have to tighten them to the exact tolerances. If they are not tightened exactly the same, the offset rails can strain and stress the rifle scope, potentially throwing off your shots, especially at longer ranges. Another issue with the Weaver rail design is the inconsistent spacing between slots. At best, this was annoying, and at worse, your optics wouldn't fit the rails properly, leaving them loose.
As for the negatives of Picatinny rails, they aren't as apparent and can be mostly avoided. For example, Picatinny rails are designed for more modern weapons, so they can cause some issues with older service rifles that load or eject from the top. Since most Pic rails are only a single piece that you attach to the rifle, this can obstruct the port and prevent you from loading and firing the weapon properly. The other big complaint people have is that a Picatinny rail adds a decent amount of weight to the firearm. Since this accessory mounting system is made of durable, rugged metal, this can't really be avoided. However, it does mean it is less likely to break.
So Which Should You Choose?
Realistically, the choice between Weaver rails and Picatinny rails comes down to the type of weapon you are trying to customize. If you have an older hunting rifle that has been passed down to you and you want an easy way to mount an optic, then attach a two-piece Weaver rail. On the other hand, for modern carbines, handguns, shotguns, and rifles, you're better off with Picatinny rails. Many of these weapons already come with the attached rails, so you don't need to change anything. Just buy the accessories you need, and you can slot them in quickly.
Regardless of your choice, our team at OpticsPlanet has assembled a ton of weapon accessories for you to choose from, and many of them attach to both Weaver and Picatinny rails. Check out our wide selection of bipods, flashlights, and night vision rifle scopes. We also have in-stock ammo for everything from .223/5.56 NATO to .308 Winchester, 9 mm Luger, and more obscure calibers.
