M4 Rifle Buyer Guides

The M4 Carbine is the spearhead of the modern U.S Infantry troops. A venerable, trusted, and truly versatile rifle that has reshaped how assault rifles are seen. While the M4 is still in military service, the urge for civilian ownership has rapidly increased.

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But can you really own an M4 in the U.S? And if you can, it is important to learn about this rifle, its pros, cons, and how you can get the most out of it. Stay tuned to learn more.

Table of Contents

M4 Overview

Taking Advantage of the M4

What the M4 Does Best


Where the M4 Falls Short

An Overview of the M4

The Colt M4 carbine also known as the M4 is a gas-operated, direct impingement, select-fire carbine. It is chambered for the 5.56x45mm NATO cartridge and has a 14.5-inch barrel and a telescopic stock. The stock is also colloquially known as the M4 stock or ‘six position’ stock.

Developed between the years 1982 to 1993, the M4 is basically a shortened and lightened version of the M16A2 rifle. The M4 began being gradually adopted by different departments of U.S Military forces in some capacity. It almost entirely replaced the M16A2 and M16A4 as the most common frontline weapons.

The reason for the popularity among the troops was its shortened size. Starting in the 1990s, the use of armored infantry vehicles and urban warfare greatly increased. The M16 rifles with their long 20 inch barrels were being found to be clumsy and cumbersome for handling in confined spaces.

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The M4 on the other hand has a 14.5-inch barrel. Allowing it to be easily maneuvered in confined spaces. This shortening of the barrel resulted in only a 200 fps drop in muzzle velocity. But when your operating range is well under 200 yards, the target won’t even notice a difference.

The M4 comes in two major variants. The M4 and M4A1. The latter features a full auto firing mode, whereas the former has a 3-round burst mode instead.

In 2009, the U.S Army took complete ownership of the M4. So Colt and other firearm manufacturers could not compete on their own M4 designs. Since fully automatic weapons are banned for sale in the U.S.

A normal civilian cannot own an actual M4 (only machine gun dealers or pre-ban M16s transformed to imitate the M4) in the U.S. So the rifles you find on the market labeled as M4’s are actually just AR-15 SBR versions.

What the M4 Carbine Does Best

The M4 was exclusively designed for close-quarter combat. Especially in confined spaces where the weapon should be easily maneuverable. In an independent survey conducted in 2010, about 89% of soldiers with the M4 expressed that their carbine was reliable in combat.

The M4 offers a reliability rate of about 98%. With the remaining issues being mostly ‘class one’ stoppages that required less than 10 seconds to clear. So the M4 can be trusted upon as a reliable combat weapon.

The next best thing the M4 has to offer is customizability. With most M4 rifles featuring a quad rail around the handguard. Plus, a top Picatinny rail (which is obvious). The M4 allows the user to mount every appropriate accessory possible.

From bipods to flip-up BUIS, there’s a lot of rail estate to let the user handle almost every situation. Additionally, the six-position telescopic stock delivers optimal adaptability for users of different physiques and with various clothing options. Having the adjustable stock really makes the weapon more ergonomic.

The shorter design of the M4 also ensures that it weighs a little less. This further improves handling and reduces fatigue with long time use. Additionally, a physically strong user can compensate for the weight by carrying extra ammo.

The M4 also has a big advantage in terms of customization. Since it belongs to the AR family of firearms. There are literally thousands of upgrades, accessories, and aftermarket parts out there to spruce up this weapon.

Additionally, the M4 is almost 80% identical to the M16 (or the AR-15). So replacement of parts and their availability is very convenient.

Where the M4 Falls Short

The M4 solved a lot of handling and ergonomic problems for the front line troops. But it came at a cost. The cost of several compromises relating to the range, penetration, accuracy, and durability.

The short barrel of the M4 means there’s less space for gasses to build up. This results in a reduced velocity of the projectile. This reduction in velocity results in lesser penetration at the target. Hence resulting in smaller wounds.

The difference of about 200 fps at the muzzle will translate to a bigger difference at further distances.

A shorter overall design means a shorter gas system. Which creates more pressure on the internal components of the action. Resulting in quicker wear and tear of those parts. The increased bolt speed also affects the durability of magazines.

Malfunctioning magazines are the biggest of complaints in the already small complaint box of the M4 carbine.

As a drawback of the smaller overall design, the rifle has a shorter sight radius which can hamper accuracy when not using optic sights. The short barrel is also prone to a significant muzzle flash that can give away the position of the shooter.

The M4 was not designed for long range use. Which can seem to be a significant drawback for people who are used to long range rifles or versatile calibers like the .308. The M4 is a close-quarters rifle and suitable for distances below 300 yards. Hence, it cannot be seen as a ‘versatile rifle’.

Apart from all this, the M4 has a direct impingement gas system. Which requires regular maintenance and cleaning. There are systems out there that can last longer without much cleaning.

How to Take Advantage of the M4 Carbine

There’s literally a gazillion way to customize the M4 carbine and transform it to suit your intended application. In fact, the modularity and customizability of this platform is what separates it from most rifle systems.

The M4 is just like the AR-15. The aftermarket is stacked with upgrades for this carbine. If you get an M4 with a railed handguard, you can look out for a good bipod or laser/light attachment. On the contrary, you can also check out the wide range of M4 handguards available out there.

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As I already mentioned in the previous section, M4 magazines have to be very strong and durable to handle the gas pressures and bolt cycle rate.

The .223 round was developed to be used with a 20-inch barrel. Some soldiers turn towards switching to this barrel length for their carbines.

To utilize the maximum potential of the round and improve the effective range of the rifle. There’s a lot of M4 barrel options out there to choose from.

Since the M4 uses a shorter gas system and modified feed ramps. Sometimes one can expect to save some money on buying a separate M4 rifle and just buying an M4 upper receiver for a quick switch. The M4, M16, and AR-15 are the same platform with different fire-switch options.

The M4 stock is great as it is. But with a myriad of options out there. You should definitely check out the best M4 stocks to choose from. Since a right cheek weld is essential for good accuracy. Some people may also need stocks with a cheek riser.


The M4 is the latest adoption by the U.S Military and has seen almost three decades of service as a frontline weapon. It is a compact version of the M16, featuring a short barrel and a collapsible stock.

The M4 was designed for close-quarter combat and ranges within 300 yards. The civilian versions are not true M4 since they lack full-auto capabilities. Plus, there are a ton of upgrades available out there to fine-tune your carbine.


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