Picatinny vs Weaver Rails: What’s the Difference?

Picatinny rails (a.k.a pic rails) or Weaver rails—which one should you choose?

They are two of the most famous rail systems, have different backgrounds, and serve different purposes.

If you need help making the right choice, read all about these two systems in this article.

TL;DR: Picatinny vs. Weaver

Relevant Characteristics Between Picatinny and Weaver

It can be challenging to discern a one-piece Weaver rail from a Picatinny rail by appearance alone. Nonetheless, the differences are there and can change the whole shooting experience, for better or worse, depending on your knowledge about them. In this table, we display their most essential characteristics. 

Similarities and Differences

Picatinny and Weaver rails serve the same purpose: enabling easy mounting and unmounting different gears on your gun. Sometimes, it's challenging to differentiate them by their looks, but the differences are there nonetheless. You better know them before making your choice. Learn what they do (and don’t) have in common below.

Picatinny and Weaver Differences

Let's take a look at some of the significant Picatinny and Weaver differences.

Rail Grooves

Picatinny rails, also known as MIL-STD – 1913 rails, tactical rails, or only Pic rails, have equally measured grooves. It is 0.206" wide, and slots are spaced at 0.394." Unlike Picatinny, Weaver rails do not have a standard measure for the slots. 

Picatinny rails have broader and deeper slots, while Weaver rails can only have one or two slots placed anywhere on the gun. Longer Weaver pieces look very much like Picatinny, but specs are not standardized. You can even get two different sizes on the same rail. 

Adjustability

While Weavers can accept accessories designed to work on a Picatinny rail, Weaver rails were initially intended to work in one or two pieces like the prolonged one, which was developed later. 

Picatinny only uses one-piece rails. Mounting a scope using two-pieced Weaver rails can be tricky, while one-piece rails are much easier to install. Because Weaver slots are uneven, they are adapted to mount any Pic rail-designed accessory. 

On the contrary, Picatinny rails can hardly accept any Weaver-like accessory. Because of their slotting system, Pic rails allow you to install the scope further on the barrel, while the same is not possible on Weaver rails. 

Rings

It's also important to consider the rings you wish to use on your gun. Weaver and Picatinny rings have unique features and may serve some purposes better than others. Here, once again, measurements are different: the recoil stopper on Picatinny rings is approximately 5mm wide, while Weaver’s are 3.8mm wide. 

Notice that not every Weaver ring has a recoil stopper, but you can mount them where there are no slots. Some specialists consider the Picatinny system more advanced, while Weavers are losing space. 

When Weaver rails were designed (around 1930), scopes were the only accessories available. Picatinny was standardized in 1995 and was designed to mount a plethora of accessories, even on the sides of the barrel.   

Picatinny and Weaver Similarities

Now let’s look at the Picatinny and Weaver similarities.

Slotted Rails and Clamps

Picatinny and Weaver rails are both slotted systems, and it's actually hard to tell one from another sometimes. It's because Weaver rails can come in one or two pieces. The one-piece rail is almost identical to Pic ones. 

They both use a clamping system to attach their accessories, and this system prevents scopes from moving with the recoil. Their rings are very similar and share the same clamping system as well, with a screw side and a clamping side. Slotted systems also ease the mounting/unmounting of scopes. If the same slots are used, there's next to no change in zero. It's a handy feature if you plan on swapping scopes between guns. 

Compatibility and Purposes

Weaver accessories mostly fit well on pic rails. Picatinny slots are larger than Weaver ones, while the contrary doesn't hold true. It happens because pic rails' slots are larger than the Weaver ones. 

That's why scope manufacturers tend to build based on the Weaver-style, so the scope can effortlessly fit in both rails. Both systems are successfully used for hunting. Pic rails tend to be heavier than Weavers (especially the two-piece set), but this gap has been closing with the development of lighter pic rails.

Anti-recoil Systems and Rings

Slotted rails have anti-recoil advantages that Picatinny and Weavers can enjoy. Albeit different in size (Picatinny rings are 5mm wide, while Weaver rings are 3.8mm), both are used as anti-recoil systems. Again, Weaver rings would fit on pic rails, but not the contrary. 

Picatinny rings are more robust and fill the whole slot. Weaver rings are smaller than pic rings, but no less reliable because of it. In the end, it's a matter of personal taste.

Advantages of Picatinny Rails

In this section, we’ll look at the pros of Picatinny rails.

Installation and Compatibility

Picatinny rails can be placed on all sides of the barrel and allow the use of several accessories simultaneously. They can also support a 20 MOA base, which can be an advantage for precision and long-range shooting. 

Picatinny rails are also more robust and allow accessories to be mounted either on the front or the rear of the rail surface. They have an ejection port relief cut, making it a heavier piece than a two-piece system.   

Surfaces and Usability

Picatinny rails have more extended surfaces. It allows several slight adjustments on your scope, regarding latitude, by merely placing your scope elsewhere on the rail. This feature is beneficial when installing recoil stoppers. 

The fact that these rails are standardized makes it easier for mounting and unmounting accessories, as well as interchanging accessories between guns. A one-pieced surface also naturally avoids alignment issues that may come upon a two-piece Weaver rail. 

Versatility and Accessories

Pic rails used to be heavy pieces of metal and would make for clumsy light hunting companions. Not anymore. Another perk that follows Picatinny rails is the Quick Detach (QD), which allows you to unmount your scope quickly to aim at closer targets. 

This feature can be handy if you need to shift rapidly between target distances. The eye relief is also more easily adjustable than on Weaver rails because you only need to move your scope back or forth on the slots. 

Picatinny rails work well with Weaver rings, adding even more versatility to the system.  

Since pic rails were officially adopted by the army and built-in on all AR-15s, a whole industry started to race for the best and trendiest accessories, like laser sights, night vision, and thermal.

The ability to house a 20 MOA scope is unbeatable when it comes to precision shooting. It can also be used to hold your hunting gear, although some may find it too heavy for the job. For those, there are lighter pic rails available. 

It's a convenient system if you have more than one gun and plan on interchanging accessories between them, as it is a one-size-fits-all approach. For those very practical reasons, many consider pic rails development of the Weaver rails. For the same reasons, pic rails tend to be more expensive than the Weaver ones.

Advantages of Weaver Rails

It’s time to look at the benefits of Weaver rails.

Adjustability

Weaver rails are usually lighter than pic rails. They are not compatible with Pic rail gear, although Weaver gear can mostly fit in on a pic rail. The positioning of the two-pieced Weaver rails is very flexible; they can be positioned almost anywhere on the barrel. 

Weaver rails work excellently on rifles with blind magazines or hinged floorplate magazines. Its two-piece system enables shooters to make a low profile, despite its thickness. In the two-piece design, one-piece goes on the front and the other on the back, making it perfectly fit for large scopes. 

For the same reason, this system avoids obliterating the ejection port. The one-piece Weaver rail solves an old two-piece's problem with alignment. 

Pricing

They are considerably cheaper than the pic rails. Additionally, it allows the use of the iron sight, unlike the pic rails. So, if you don't want to buy an expensive scope right now, that may be the best choice. There are also affordable scopes that are compatible with Weaver rails. If there's no need for pinpoint precision at thousands of yards away, it's possible to pull up efficient gear for a reasonable price. Some older and cheaper guns can only work with Weaver rails, so that's another way of saving.  

Historical Guns/Aesthetics

Weaver rails are the first of their kind, and some old rifles only accept Weaver rails. Some others may find the pic rail's aesthetic rather brute. Most historical rifles will only get Weaver rails, which was the sole rail system around for a while. Historical rifle collectors and other enthusiasts more concerned about aesthetics will probably go for a two-piece Weaver rail for their guns.  

Weaver mounts work quite well as hunting gear. They are considerably lighter than pic rails, which makes a lot of difference if you need to go hiking or climbing with them. It's perfect for hunting in the woods unlike a 20 MOA scope, which would be wasteful and useless. 

The one-piece option solves possible problems with alignment, but you also have to consider its additional weight. It wouldn't make any sense to place a massive pic rail on a historical rifle, so Weaver rails have their place secured in this niche. 

If aligned correctly, it can mount short and medium-range scopes and any other mounting system, with the additional advantage of not rendering the iron sight useless. 

What About Dovetail Rails?

Dovetail is another mounting system. It doesn't have slots, like Weaver or Picatinny. Instead, it uses sliding brackets in an upside-down trapezium shape, hence the name. It's one of the oldest assembling techniques out there and was already very common on wood-crafting before being mounted on guns. 

It's mostly mounted on the top of the receiver, but they can also be found on the left-side of some rifles’ receivers. This specific kind of mounting is nicknamed the Warsaw Pact rail and was commonly used by the Soviet and Warsaw Pact armies.

Its slides are made of normalized cast iron but can also be found in aluminum and other materials alike. Dovetails are available in both low and high-profile models. While the low-profile design is thinner on the saddles and bases, the high profile uses thicker rails and saddles.

Dovetail rails may vary in size and shape, according to the manufacturer. The most commonly used sizes are 11mm and 3/8 inch, also known as "tip-off rails." Three-eighths-inch dovetail rails are made of two parallel grooves and are very cheap. Those tip-off rails are often used on air rifles and rimfire rifles. With those rails, scopes can be mounted and unmounted effortlessly. There's no need for special tools either. 

Because dovetail-designed accessories are not restrained by slot positioning, you can place them wherever you need along the rail. Even though dovetail rails can't support more advanced scopes, they can work quite well on a secondary gun, provided you don't expect exceptional accuracy. 

Dovetails and Picatinny can work together if conveniently adapted. Dovetail measurements, like Weavers, are not standardized, which poses a problem for accessory developers.

Bottom Line

Weavers are light, cheap, and perfectly compatible with short or medium-range scopes, for which they were initially designed. They are also the only option for many antique/historical guns. The two-piece design is ideal if you want to avoid problems with alignment while installing.  

Picatinny was officially developed and standardized for military purposes back in the 1990s. For those reasons, they are the way to go if you want to gear up your gun with the newest accessories on the market. Their weight doesn't make it ideal for hunting, although some more recent versions are built lighter.