AR-15 vs M4

What are the Differences and Similarities Between AR-15 vs M4?

Sharing is caring!

Reading Time: 12 minutes

AR-15 vs M4


M4 vs. AR-15 are very popular rifles within the U.S and the gun community. You have probably identified the M4 rifle with the U.S military troops, while the AR-15 is commonly owned by millions of civilians within the U.S.

Brief History

The above two rifles are very similar but also share differences. Historically, the AR-15 from Colt Firearms was designed for military use in Vietnam. Later, it underwent significant improvement, and the M16 was born. It was designed as a lightweight rifle with high speed and increased capacity for rounds. The AR-15 had a similar design to the AR-10 but with a lot of improvements. Also, it gained popularity among civilians, which led to the large production of this firearm.

The M4 can be considered as an improved version of the M16. In the 1980s, the American military needed a shorter and lighter firearm than the M16. The M4 version was developed to meet the demand. For so long, it has been adopted by the U.S armed forces as their primary rifle for close-quarter shooting. The M4 has also experienced an evolution to XM4 that is designed with AR-15 and Colt Commando features. It is a reliable and effective weapon for the military.

Let’s focus more on the differences between the M4 and AR-15. Also, we shall look into their similarities.

Differences Between M4 and AR-15


The barrels between the two vary. For the M4, it’s 14.5 inches (370mm) while that of an AR-15 is 16 inches (406.4mm). However, some owner of the AR-15 rifle does customize the barrel to 20 inches. Due to the short barrel on the M4, it has a shorter gas tube; therefore, it has a more definite feed ramp to handle decreased pressure. M4 being more of a military rifle, it has an hourglass shape that accommodates grenade launchers on it.


M4’s caliber is 5.56x45mm NATO (.223 in) while the civilian AR-15s varies by the manufacturer. However, the AR-15 can be anywhere from .22LR to .50 Beowulf due to its high customization adaptability. The upper part can easily be replaced to enhance the chambering capability of different rounds.


Another difference is that M4 rifles are burst fire and automatic, while over 90% of the AR-15s operate on a semi-automatic setting. Since 1986, the full automatic AR-5 rifles are only legal for military and law enforcement personnel.


In the current market, the AR-15 is produced by different companies, including Colt, while the M4 is only manufactured by FN Hernstal and Colt for U.S military services. From this perspective, you understand why the AR-15s are highly customized, therefore the variation of the barrel, caliber, and other components.


Can civilians own M4? Full automatic M4 rifles are meant explicitly for U.S military service and not civilians. That’s mean it’s illegal for a civilian to own one. However, as a civilian, you can buy the pre-1986 M4 Select Fire Colt. On the other hand, it is legal for citizens to own the AR-15s for their personal use, including hunting and self-defense.


The M4 is categorized as an assault rifle while the AR-15 is a type of rifle. Assault rifles have the safe, fire and full auto capabilities. Assault rifles are more rapid and are designed for military use. Conversely, the AR-15 is semi-automatic and delivers a rifle performance. However, when features such as barrel and overall length of an AR-15 are customized, the category might be affected according to the NFA specifications.

Similarities – What are the Common Parts for AR-15 and M4?

The reason a large number of people refer to the AR-15 as an assault rifle, it’s because of the similarities it shares with the M4. What is common about them?


Both of these rifles are American products with a remarkable history.

Identical components

Among the identical components in AR-15 and the M4 includes the following: charging handle, trigger assembly, bolt carrier group, other parts of the upper and lower receiver.

Advantages and Disadvantages of M4

To Know the Advantages and Disadvantages of AR-15

AR-15 vs. M4: Which is Better?

It is challenging to decide between the two. However, owning an AR-15 is very easy and straightforward since civilians can easily access it from a dealer and acquire it legally for your personal use. Also, you can easily build your own AR-15 at home using the 80% receiver kit or a stripped lower and lower parts kit. That even allows you to do any custom work on it to your preference. Owning an M4 for ordinary citizens is a challenge. However, they are reliable and effective firearms for military use.

Sharing is caring!

Leave a Comment

Your email address will not be published. Required fields are marked *

CommentLuv badge