Why did Colt produce the M5 family of rifles?

Gear & Tech

By Travis Pike

June 20, 2023

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SIG Sauer and MCX Spear won the Next Generation Squad Weapon (NGSW) contest, and the rifle variant will be crowned the M5. This is a graduation upon the M4, which served the United States Army for decades. The M4 leaves big shoes to fill, and hopefully, the SIG rifle is ready to step up. With that said, anyone doing a search for the M5 online might stumble across the Colt M5, which seems confusing.

Colt was the manufacturer of the M4 rifle and, for over 100 years, produced weapons for the United States military. In the modern era, they were most famous for the M1911 until the M9 Beretta took over.

So what about Colt’s M5?

To be clear, the M5 is not a military designation but a designation added by Colt. The company is clearly building on its famed M4 design and capitalizing on its success. The M5 was first shown in 2017 at the Bahrain International Defense Exhibition and Conference, a military and law enforcement-type event where new companies can show off assault rifles, machine guns, missiles, drones, and more in hopes of fat military contracts.

The M5 isn’t just a rifle but more like a family of rifles. When you say Colt M5, you could be describing one of several configurations.

Colt makes the M5 in various barrel lengths, but other than barrel length, they are mostly the same. Each model has its own model numbers. The Model M5 R0950-10 has a 10.3-inch barrel; the Model M5 R0950-11an 11.5 inch-barrel; and the Model M5 RO950-14 has a 14.5-inch barrel.

Colt had used a similar naming system before when it purchased the AR-15 design from Armalite and created the CAR-15 series, which is often boiled down to the CAR-15 carbine, but in reality, the whole series of Armalite rifles were CAR-15s.

Colt also produces the famed Colt SMG under the M5 designation. The Colt M5 SMG is a 9mm subachine gun. It is very different internally than the standard M5 but does feature some of the more modern touches the M5 implemented.

What’s new with the M5

The M5 looks a lot like an M4, and it certainly follows in that gun’s steps. The biggest difference is in their operation systems. The M5 swaps the M4s and Stoner’s direct impingement for a short-stroke gas-piston design. Short-stroke gas piston systems have been found to be more reliable, especially with shorter barrels, and they also tend to handle suppressor use better than DI guns. It’s a system that’s all the rage with the current commando types in the form of the HK 416D. It’s an interesting change, but many feel that Colt is behind the curve on short-stroke gas piston systems.

Colt also modified the barrel slightly to better ventilate gas and improve air circulation and barrel cooling.

Outside of the system change, Colt has finally seen fit to bring its rifles into the modern era.

The M5 ditches the front sight base for a low-profile gas black and Geissele Super Duty rail system. This rail is an M-LOK design that’s as modern as it gets. It’s also the rail system of the URG-I, the design used by the U.S. Army Special Operations Command.

Colt has outfitted the rifle with Magpul stocks and magazines and a new lower receiver. This lower receiver features ambidextrous controls to allow for a smooth transition for any shooter. Ambidextrous controls are a very nice touch on a modern rifle and greatly improve a weapon’s ergonomics.

But why did Colt make these rifles?

A Force Element from 2nd Commando Regiment, Australian Defence Force dismounting an MC-130 aircraft during airborne insertion operations over the Great Barrier Reef of the shores of Rockhampton, Australia during Talisman Saber 2011. Australian and U.S. Special Forces worked in a combined effort during TS11. (Photo by U.S. Army Staff Sergeant Aubree Clute 1st Special Forces Group (Airborne))

In 2017, the Australian Defense Force Special Operations Command (ADF SOCOM) sent Colt a specification for a new rifle. It wasn’t a contract, invitation to bid, or anything other than a spec. Colt took them up on that spec and produced the M5. However, it doesn’t seem that the company sold any of the rifles to ADF SOCOM. Yet, Colt took the opportunity to innovate and has since marketed the rifles globally.

As far as I can find, Colt’s M5s haven’t produced any major contracts of note. Still, it’s nice to see an old American company finally do a little innovation.

Feature Image: A Colt M5 (top) and a Colt CMK (bottom) at IDEX 2023 (Photo by Mztourist/Wikimedia Commons)