M-Lok vs Picatinny Rail System: What Is the Difference?

If you’re trying to make your firearm more accommodating, you’ll want to mount accessories to it. Fortunately, when it comes to accessory mounting systems, there are two gold standards from which to choose – the M-Lok or Picatinny.

Both systems offer exceptional performance, but let’s break down each option.

Picatinny Rail: MIL-STD-1913

As the first rail system of its kind, Picatinny Rails quickly became the go-to option for mounting scopes and other attachments to rifles of different shapes and sizes. The name Picatinny stems from the location where it was developed – the Picatinny Arsenal in New Jersey.

Although the original rail system was created in 1995, it’s undergone a few upgrades over the years. The most notable revision was in 2009 when NATO recommended the manufacturer switch to a metric system and update the clamping method.

This change made it easier to zero out any scopes attached to the rail and allowed for stronger grips between the gun and the attachment so they don’t fall off.

A Pic Rail is mainly used to attach optics, but you can attach accessories to other parts of the rifle like flashlights, front handles, bipods, and more.

M-Lok: Magpul Modular Lock

While the Picatinny Rail System was the gold standard for over a decade, Magpul decided to create the M-Lok system in 2007, although the version we know today didn’t exist until 2014.

Unlike Picatinny rails that attached to specific parts of the gun, Magpul developed a revolutionary “free-float” design. This meant you could put the handguard over the rifle barrel and start attaching accessories immediately.

While a Picatinny Rail system uses grooves, an M-Lok system uses holes and T-shaped screws for faster and easier mounting. (1)

M-Lok vs. Picatinny: Specifications and Info

It’s hard to say definitively whether one rail system is “better” than another. However, many shooters prefer the M-Lok because it’s easier to use, but it’s not quite as durable as Picatinny.

Here’s a comprehensive breakdown of factors to consider when comparing the M-Lok system to a Pic Rail.

Attachment Methods: M-Lok vs Picatinny

If you’re going to attach a Picatinny Rail to your rifle, you need to screw the piece into your firearm so that it’ll hold steady, even after repeated outings. So, if you want to mount an optical sight and a front handle, you need two individual pieces.

By comparison, M-Lok systems use a free-float design that attaches to the barrel and itself. Not only is it much easier to install an M-Lok rail to a rifle, but you can mount accessories on all sides immediately without needing multiple pieces.

Another advantage of the M-Lok system is that you can attach Picatinny rails to the negative spaces and combine both systems to get the best of each.

However, one significant issue you can experience with Picatinny is that they will come loose the more you fire your gun. The vibrations and heat will loosen the screws, so they’ll eventually pop out.

Handguard Profiles: Picatinny vs M-Lok

As a free-float design, M-Lok rail systems make the barrel of your rifle seem thicker and bulkier, particularly once you mount attachments. However, it also provides an immediate military or tactical appearance, which can be visually appealing for most shooters.

Since you have to attach Pic rails individually, they don’t affect the silhouette of a rifle too much unless you’re adding multiple pieces at once. However, the Picatinny does have a rigid, “cheese grater” appearance that is less ergonomic than the M-Lok.

Comfort, Ergonomics, and Handling

The design of a Picatinny system is actually pretty sharp when it’s brand-new. Sometimes, shooters can cut themselves if they’re not careful when grabbing an accessory like a front handle.

Regarding ergonomics, an M-Lok system handles better because it wraps around the entire barrel. So, you can incorporate more attachments without needing multiple pieces.

Conversely, a straight-rail Picatinny doesn’t have that all-around access, but the bulkier quad-rail does. That rail has a slightly uncomfortable “cheese grater” feel that may require rail covers.

When talking about handling, M-Lok systems are generally easier to master because they make accessory mounting so efficient. Plus, you can swap and reposition attachments quickly.

Weight

One of the biggest complaints about Picatinny rail systems is that they’re too heavy. When mounting one to your rifle, you’ll notice an immediate difference, forcing you to adjust your shot accordingly. While a single rail won’t do too much, adding more pieces will exacerbate the situation.

M-Lok systems are much lighter and nimbler, making them ideal for most civilian and military situations.

Price and Compatibility

Because Picatinny systems came first, all accessory manufacturers made their products compatible with this rail type.

Today, it’s much easier to find M-Lok compatible accessories when compared to a Picatinny. Also, as we mentioned, you can attach small Picatinny-style rails to an M-Lok, meaning you can use both systems simultaneously.

Since Pic rails are heavy-duty, they’re often more expensive than M-Lok, which uses more lightweight and affordable metals.

Bipods

You can find many bipods available for both Picatinny and M-Lok. Ironically, Magpul makes bipods for both rails, even though the company produces the M-Lok system.

Durability

Here is where the Picatinny outshines the M-Lok. If you’re using a heavy-duty weapon, you want something that can withstand a lot of wear and tear. That’s not to say that M-Lok rails are weak, just not as durable as Picatinny.

M-Lok vs KeyMod vs Picatinny vs Weaver Rail

Here are some notable differences between these four rail models:

• History – Weaver Rails were first, then Picatinny, KeyMod, then M-Lok.
• Spacing – Weaver Rails have a 0.180mm space between ridges, while Picatinny has 0.206mm. KeyMod and M-Lok rails use larger holes.
• Number of Sides – Pic rails are usually unidirectional, but you can buy quad rail designs with four sides. M-Lok has four sides standard, and KeyMods offer eight mounting options.
• Adjustability – To move an accessory on a Picatinny or Weaver, you must detach and reattach the piece to a new groove. With the M-Lok or KeyMod system, you can shift the piece back and forth within the same hole or re-attach it to a different one. (2)

How Does the M-Lok System Work

If you’re sold on the M-Lok system, take a look at: how does the M Lok system work. We go every everthing you need to know to get up and running with the M-Lok today.

Top Drop in Lightweight Handguards

If you’re looking for recommendations on the best handguards out there, take a look at our article on the top drop in lightweight handguards. We cover the best options on the market today.

FAQ

Why have people switched to KeyMod or M-Lok instead of Picatinny?

People are switching from Picatinny to M-Lok because the latter option is lighter, more accommodating, cheaper, and easier to install.

Will Picatinny fit M-Lok?

Yes, you can buy Picatinny sections that fit within an M-Lok rail system. You can also buy T-screws to fit traditional Picatinny rails so they’ll be compatible with M-Lok.

What is the point of M-Lok?

The point of the M-Lok system is designed to mount accessories to your firearm without attaching them directly to the gun. As a modular locking system, you can add, remove, and swap accessories as needed.

Does the military use M-Lok?

Yes, the military does use the M-Lok system because of its distinct advantages over a traditional Picatinny. The M-Lok has better airflow, lighter weight, and smoother handling when firing, making it an ideal addition to any military firearm.

References

1. Magpul, M-LOK 2015 FAQs, retrieved from https://web.archive.org/web/20190407022314/https://www.magpul.com/Files/Images/PDF/M-LOK/M-LOK_2015_FAQs.pdf
2. Brownells, Picatinny Rails, Weaver Rails, What’s The Difference, retrieved from https://www.brownells.com/aspx/learn/learndetail.aspx?lid=10724