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In this article, we’re examining the differences between two very similar types of guns – the M16 and the AR-15. The M16 is a type of AR-15, but we’ll dive deeper into the details below.
We’ll start with a basic rundown of both types of guns, and highlight their differences and their similarities.
We hope you come away from this article with a more comprehensive understanding of this somewhat confusing area of firearms.
What is an AR-15?
An AR-15 is a lightweight semi-automatic rifle. It is one of the most popular guns in the United States and is certainly the center of its fair share of controversy.
What Was the AR-15 Designed For and What Does AR-15 Stand For?
To understand the AR-15, it’s important to understand its history. Originally, the AR-15 was developed by ArmaLite Rifles (AR, hence the name) in the 1950s for use by the US Military. It was a gas-cooled, select-fire, magazine-fed rifle. Despite what uneducated and sensationalist media sources might tell you, AR does not stand for assault rifle.
In 1959, ArmaLite sold the patents to Colt, who eventually developed a semi-automatic version of the AR-15 for civilian use.
Colt’s patent expired on the product in the 1970s, and now all sorts of manufacturers make AR-15s. Perhaps what is so popular about this gun is its wealth of customization options. You can get many types of AR-15s with different customization options, including different barrel lengths and designs, grips, receivers, stocks, and more.
AR-15s also owe their popularity to their functionality. They are accurate, precise, and reliable. Their usage is wide, and are often used in hunting, targeting, and self-defense scenarios.
When Did the AR-15 Become Legal?
The AR-15 became legally available to civilians when Colt developed the semi-automatic version for civilian use in 1959. Of course, there are now various gun control laws pertaining to AR-15s depending on where you live.
AR-15 Types
One of the main appeals of an AR-15 is that they are so customizable. They feature a wide array of interchangeable parts, which can be swapped for varying degrees of functionality. As a result, it’s difficult to categorize them into official “types”, but there are some categories upon which AR-15s tend to differ:
Barrel Length
Barrel length is one of the main customizable features that leads to a big difference in an AR’s overall performance. Generally speaking, shorter barrels are geared more toward maneuverability and control, while longer barrels are geared more toward accuracy and velocity.
The design of the barrel itself may also result in higher durability (by using higher quality materials such as stainless steel). The barrel also determines the twist rate.
Weight
The weight of the AR-15 influences its performance as well. Heavier ARs use thicker materials, often emphasize durability, and also increase heat absorption from the barrel. Lighter ARs tend to emphasize portability, at the expense of some of the aforementioned benefits.
Gas System
The gas system works like this– the gas is going to travel through both the gas block and the gas tube, then into the receiver. Once in the receiver, it powers the bolt carrier group and automatically loads the next round. Also on the AR-15 with the gas system, the AR-15 is going to have what is called a "gas port". The gas port is a small hole on the barrel of the AR-15. The purpose of this hole is to vent gas with every shot.
AR-15s have four types of direct-impingement gas systems: pistol, rifle, carbine, and mid-length to choose from. They also work with gas piston technology which isolates the gas in a separate chamber.
Other Features
Many other features can be customized on an AR-15. This is why it’s so difficult to separate it into categories, and also why it’s such a popular gun. You can customize the trigger, the stock, the pistol grip, the gas system, and much, much more.
What is an M16?
Next up, we have the M16. The M16 is a fully-automatic military rifle, which has been in use in the United States military since the Vietnam War.
Technically speaking, an M16 is a variation of AR-15. This means that all M16s are types of AR-15s. However, both have become so popular in their own right that most people might not use this distinction.
When Was the M16 Made and What Was the M16 Designed For?
To understand more about the M16, we need to look at its history. As we mentioned above, the AR-15 was originally developed by ArmaLite rifles, who sold the patent to Colt. Colt used the AR-15 to develop the M16 (Model 16) rifle, which was a fully automatic version of the AR-15 (and also had a select fire switch). These rifles were shipped to soldiers in Vietnam in 1964, and they have been in use in the United States military since.
The M16 is technically legal for purchase in most States (with specific laws surrounding licensing and tax stamps). However, M16s were only sold for civilian use until 1986. These are the only M16s that are legally purchasable, with the rest belonging to the USA Department of Defense. As such, it will be extremely difficult and extremely costly (roughly $30K) to purchase an M16.
The M16 has gone through various development within the military, and we will explain some of these developments below.
Who Makes The M16?
Although the M16 was originally developed by Colt Manufacturing, current models have been made primarily by FN USA since 1988.
What Does M16 Stand For?
As mentioned above, M16 stands for Model 16 rifle. It was the original version of the rifle developed by Colt.
Can You Legally Own an M16?
The M16 is technically legal for purchase in most States (with specific laws surrounding licensing and tax stamps). However, M16s were only sold for civilian use until 1986. These are the only M16s that are legally purchasable, with the rest belonging to the USA Department of Defense. As such, it will be extremely difficult and extremely costly (roughly $30K) to purchase an M16, and it would have to be a civilian version produced before 1986.
M16 Types
The M16 has gone through many variations through its product lifespan, and there are now 4 variations used in the US Military (A1, A2, A3, A4). Below are a few of the most popular variations, which will help you understand how this product evolved:
M16 vs M16 A1
M16
The first model of the M16 was called simply that. It was used originally by the US Air Force. Notable features included triangular handguards, fully automatic, a three-pronged flash suppressor, and no forward assist.
M16 A1
The M16 A1 was the first major development in M16s. It was finalized in 1967 and was made until 1982. It was very similar to the original M16 but included forward assist, as well as notches in the bolt carrier.
The M16 continued to go through various developments and continued to be improved for military use.
M16 A2 vs. M16 A4
M16 A2
The M16 A2 was the next major development in M16 technology after the A1. The A2 was requested by the USA Marine Corps after experience in Vietnam with the A1. The A2 had extensive developments over the A1 – including STANAG NATO chambering, a thicker barrel (for more durability and longer sustained fire), a new rear sight, a modified front grip, and more. It was seen as a more durable, better performing version of the A1.
M16 A4
The fourth generation of M16s, notable features of the A4 include a quad Picatinny rail, carrying handle, and other notable features. It continues to be used by various arms of the US military, and some A4 models are available for International purchase.
XM16e1 vs. M16 A1
M16a1
As mentioned above, the M16 A1 was the first major development in M16s. It was very similar to the original M16 but included forward assist, as well as notches in the bolt carrier.
XM16e1
The XM16e1 was essentially the same weapon as the M16A1 (and the two are often referred to interchangeably). The difference is that the M16A1 was the name given to the final production model of this gun.
AR-15 and M16 Comparison
As you can see, the civilian AR-15 and M16 share a common history and are very similar guns. In this section, we’ll help you understand the differences and similarities between these guns. Let’s start with the similarities:
AR-15 and M16 Similarities
The Technicality
As you can see from the sections above, the M16 is just a military adaptation of the AR-15. So, technically speaking, all M16s are AR-15s, but not all AR-15s are M16s.
And it is generally true that AR-15s are semi-automatic while M16s are fully automatic, although this hasn’t always been the case. Technically, an AR-15 doesn’t need to be semi-automatic to be considered an AR-15, it has just become the common way that they are referred to.
As you can see, this is all about technicalities. Most people wouldn’t use these distinctions in common speech, so it would still be more than acceptable to refer to them as separate guns.
Upper Components
Generally speaking, the upper components of an AR-15 and M16 are interchangeable. Of course, there are so many models of each gun so we can’t say this with 100% accuracy, but it is mostly true. Because all M16s are technically AR-15s, the guns use interchangeable parts.
The major differences stem from the lower receiver, which we’ll examine below.
Military Design
The similarities between these guns can be better understood because they were both developed for military use. ArmaLite Rifles developed the AR-15 for military use in the 1950s. When the patent was sold to Colt, they adapted it further for military use, developing the M16.
Differences Between AR-15 and M16
History
Understanding the differences between the AR-15 and M16 can be largely understood by the history of the two. We examined the history of both guns above, but it’s worth mentioning here in understanding the reason why these two guns differ.
Originally, a rifle was developed by ArmaLite in the 1950s for supply to the US military. ArmaLite sold the rights to this rifle to Colt, who made a fully automatic version to supply the US military – named the M16. The semi-automatic version was sold for civilian use, and is generally referred to as simply the “AR-15”.
Semi-Automatic vs Fully Automatic
As you can see, based on the way these rifles were developed, the very important difference between the two is that the M16 is fully automatic, while the AR-15 is semi-automatic.
A fully automatic weapon will continue to fire if you hold down the trigger, while a semi-automatic weapon requires repeated trigger pulls to fire rounds.
And while you can modify an AR-15 to be fully automatic, it is highly illegal.
And yes, technically there have been AR-15s sold throughout history that were fully automatic, but the generally accepted difference between these guns is that the M16 is full auto while the civilian AR-15 is semi.
That being said, there are so many variations of both types of guns. The M16 has gone through many developments for military use, while the AR-15 continues to offer many different customization options.
Cost and Availability
Another major difference between these two guns is their availability to civilians.
As mentioned above, aside from certain M16s manufactured before 1986, there is no legal M16s for civilian use. The result is that available M16s are extremely expensive and rare (we’re talking about $30K or more!).
On the contrary, AR-15s are highly available and sold widely. AR-15s will cost you roughly $500-$2000 depending on quality.
How Much is an AR-15 and How Much Does an M16 Cost?
One major difference between these two guns is their availability to civilians, which primarily determines their price.
As mentioned above, aside from certain M16s manufactured before 1986, there are no legal M16s for civilian use. The result is that available M16s are extremely expensive and rare (we’re talking about $30K or more!).
On the contrary, AR-15s are highly available and sold widely. AR-15s will cost you roughly $500-$2000 depending on quality.
How Much Does an M16 Weigh and How Much Does an AR-15 Weigh?
Both rifles weigh about the same, seeing as how they are both technically AR-15s. The primary difference will be the make and model of each, and the components which are installed. Both weight about 6.5 lbs, generally speaking.
AR-15 Dimensions
Of course, because the AR-15 is such a customizable weapon, its dimensions can change from gun to gun. Here are the dimensions for an ArmaLite AR-15, which are representative of “average” AR-15 dimensions:
Mass: 6.55 lb.
Length: 39 inches.
Barrel Length: 20 inches.
M16 Dimensions
Similar to the AR-15, the M16s dimensions vary based on the gun. Here are the dimension for a standard M16:
Mass: 6.4 lb.
Length: 39.5 inches.
Barrel Length: 20 inches.
Difference Between AR-15 and M16 Lower Receiver
As you can see, based on the way these rifles were developed, the very important difference between the two is that the M16 is fully automatic, while the AR-15 is semi-automatic.
A fully automatic weapon will continue to fire if you hold down the trigger, while a semi-automatic weapon requires repeated trigger pulls to fire rounds.
These differences are primarily due to the guns’ lower receivers. The M16 uses a different hammer, disconnector, trigger, and safety select lever with an auto sear. This makes it capable of burst-fire or full-auto fire. The AR-15’s lower receiver is not able to perform these functions – only allowing the user semi-automatic fire capabilities.
And while you can modify an AR-15 to be fully automatic, it is highly illegal.
And yes, technically there have been AR-15s sold throughout history that were fully automatic, but the generally accepted difference between these guns is that the M16 is full auto while the civilian AR-15 is semi.
Top Pick Between AR-15 and M16
And the verdict! What’s the best choice between an AR-15 and an M16? Well, to be honest, you only have one choice!
An M16 is certainly a formidable gun, but aside from a few made before 1986, it is only legal for military use. This means that civilians cannot buy them unless they are interested in spending tens of thousands for one made decades ago.
Therefore, your top choice is going to be an AR-15. Luckily, there are so many makes and models, and so many degrees of customization. An AR-15 is a versatile semi-automatic rifle, and this versatility has resulted in its immense popularity.
Conclusion
Thanks very much for reading our comparison guide between the AR-15 and the M16. The differences and similarities should be clear by now, and we hope we’ve helped you to gain some clarity in this complicated area of firearms. The differences might not be as big as you expected, but they make a big difference in how these guns are used.
People Also Ask
Before we wrap up, let’s check out some of the most frequently asked questions about M16s and AR-15s.
AR-15 vs M16, Which Came First?
The M16 is just a variant of the AR-15, so the AR-15 was developed first (by ArmaLite Rifles in the 50s).
What is the M16 vs AR-15 Bolt Carrier?
Because there are so many types of M16 and AR-15, the answer to this question isn’t always the same. Generally speaking, the M16 bolt carrier is more extensive to allow for a full-auto sear.
What is the Muzzle Velocity of AR-15 vs M16?
Because there are so many models and variants of AR-15s and M16, they will have varying muzzle velocity depending on many different factors. For example, the length of the barrel will make muzzle velocity higher or lower.
How Many Rounds Does an AR-15 Shoot Per Minute?
It depends on the capabilities of the shooter. An AR-15 is a semi-automatic gun that requires repeated trigger pressings to work. Therefore, the rate of fire will be determined by that. For example, an experienced AR user could fire about 30 rounds in 10 seconds.
What Caliber is an AR-15 and What Caliber is an M16?
Both guns can support many different calibers, so the answer will differ depending on the type of AR-15 and type of M16.