Ultimate M16 Guide

Ever wanted to learn about the famous M16? Want about build an M16 clone or even buy a retro M16 rifle? This guide covers everything M16 and where you buy, build, and learn about this iconic classic American rifle.

What is an M16?

The M16 is a 5.56-caliber air-cooled, gas-operated, magazine-fed assault rifle developed by the United States and first fielded by US Army Special Forces in Vietnam.

It quickly became standard issue for the American military and is widely recognized as the most reliable standard-issue service weapon for the modern battlefield.

The M16 has been a prominent fixture in major conflicts worldwide since the 1960s and is currently used by 15 NATO countries.

The M16 has revolutionized warfare with its lightweight construction and firepower.

It is much lighter than the original battle rifles from World War II, allowing soldiers to carry more ammunition and move faster. Its high rate of fire and accuracy make it effective against a variety of targets, and its air-cooled, gas-operated system allows for sustained fire.

It’s plastic and metal parts make it more durable than wood and steel weapons and more resistant to the elements.

The M16’s legacy will live on forever due to its iconic status as one of the most important innovations in the history of human warfare.

Its high rate of fire, accuracy, and durability have made it the preferred weapon in many conflicts, and its lightweight design has enabled soldiers to operate more efficiently and effectively than ever before. Its popularity will likely endure for many years to come.

Buy an M16 Clone

Want to buy a civilian legal M16 clone? Here are your options for current complete M16’s and M16 Clones.

Harrington & Richardson M16

The H&R M16 rifle variant is a scaled-down version of the AR-10, with an ambidextrous charging handle located within the carrying handle, and a narrower front sight “A” frame.


H&R was acquired by Palmetto State Armory during the Remington Bankruptcy and they have been using the Harrington and Richardson line to produce the M16 (fingers crossed for an M1 Garand in the future).

H&R offers several models including the M16A1 and M16A2.


H&R M16’s Best Value

Caliber:  5.56 NATO
Barrel Length:  20” 

Stag 15 Retro

Stag Arms makes the popular Stag 15 AR-15 rifle. So it’s no surprise that the Stag Arms Retro AR-15 is a popular build amongst gun enthusiasts, as it is a throwback to the original AR-15 designed by Eugene Stoner in the 1950s.

Stag 15 Retro M16 style rifle

The Stag 15 Retro is a great option for anyone looking for a clone of the M16. The Stag Retro model isn’t exactly true to one model variation of the M16 but it does feature some of the classic M16A1 features as well as some of the M16A4 features.

The flexacility of the removable top handle is a great option and can allow for easy optics mounting if you don’t want to run iron sights.

Stag 15 Retro M16 style rifle

Stag 15 Retro

Caliber: 5.56MM NATO
Barrel Length: 20″

Brownells BRN-10A

The Brownells BRN-10A is a unique M16 variant because it is the only one that is modeled after the original AR-15 Sporter-1 (SP1) but with an upgraded 20″ barrel, bayonet lug, and forward assist. It also features an A2-style compensator and an A2-style rifle buttstock, as well as an ergonomic magazine release and an A2 pistol grip.

It is one of the few M16 variants that features an aluminum body magazine with a low-friction follower, which makes it more reliable and durable.

Its fixed stock, A2-style front sight and adjustable rear sight make it perfect for hunting or competition shooting.

Last but not least, its unique muzzle device is its permanently attached compensator, making it a great choice for those who want to control the muzzle climb more effectively.

All in all, the Brownells BRN-10A is a great choice for any gun enthusiast looking for a unique M16 variant that is reliable, durable, and most of all, accurate.

Sadly, Brownells no longer makes them in complete rifles and you must purchase the parts and assemble them yourself.

Bushmaster XM-15 Rifle Series

The Bushmaster XM-15 Rifle Series is a family of semi-automatic rifles chambered in 5.56x45mm NATO.

These rifles feature a smooth handguard and lack a front sight, making them highly accurate and reliable.

They feature a 20-inch, 1:7” RH, button-broached, and chrome-lined barrel, a flat-top receiver with MIL-STD-1913 rail at the 12 o’clock position and a fixed A2 rifle buttstock.

They also have an ergonomic magazine release, forward assist, and an aluminum magazine with a low-friction follower.

What are the types of M16 variants?

The M16 was eventually replaced by the M4 which kept most of the design features of the M16. Now you can by civilian legal variants or even assemble your own M16 clone.

M16 Rifle

The M16 is one of modern warfare’s most iconic weapons. With more than 8 million fielded to soldiers in over 80 countries, it has seen its fair share of combat.

The M16’s most popular variants are the M16A2 and M16A4, both used by American troops in Iraq and Afghanistan.

The M16 features a 20-inch barrel and a mix of plastic and metal parts, including an A-frame front sight assembly.

It is designed to be lightweight, accurate and deadly. Its accuracy and lightweight construction give it the ability to fire multiple rounds in rapid succession and make it ideal for combat.

The M16 is being phased out in favor of newer weapons that can fire more powerful and accurate ammunition, however, its legacy will continue to live on.



The M16A1 is a unique variant of the M16 rifle because it was adopted by many countries around the world, and its design has been modified and adapted to fit different needs.

It is the oldest variant of the M16 and the most widely used due to age and large production numbers.

It is commonly seen in military and police forces worldwide, such as the Canadian Forces, the Malaysian Armed Forces, Royal Brunei Armed Forces, and the Mexican Marines.

The M16A1 is outfitted with an A2-style handguard, allowing for greater shooting control and better accuracy from the M1 Garand.

It is also equipped with a built-in carrying handle, allowing easy transport and handling.

Furthermore, the M16A1 can also be customized with various accessories and attachments, including M203 grenade launchers, ACOG scopes, and bayonets.


H&R M16A2

The M16A2 5.56mm rifle is a product improvement of the M16A1 rifle, developed in 1979 in response to requests from the United States Marine Corps. It is a lightweight, air-cooled, gas-operated, magazine-fed, shoulder- or hip-fired weapon designed for select fire (3-round bursts) or semiautomatic fire (single shot) through the use of a selector lever.

This variant is designed with a fully adjustable rear sight, a compensator to help keep the muzzle down during firing, a redesigned handguard with a round contour for a better grip, a new buttstock and pistol grip made of a tougher injection moldable plastic.

This improved rear sight can be easily adjusted for windage and range, a modified upper receiver design to deflect ejected cartridges and a burst control device.

It also has a heavier barrel with a 1 in 7 twist to fire NATO standard SS109 type (M855) ammunition. This further increases the effective range and penetration of the rifle cartridge.

The M16A2 has a maximum effective range of 550 meters and a muzzle velocity of 2,800 feet.

With a 30-round magazine, it has a total length of 39.63 inches and a total weight of 8.79 lbs.

The M16A2 was manufactured by Colt and FNH USA, the M16A2 is used by the US Navy, USMC, US Army, and USAF.



The M16A4 is the fourth generation of the M16 series, a 3-round burst rifle currently used as a service rifle in the United States Army.

It is equipped with an upper receiver, a removable carrying handle, a built-in full-length Picatinny rail for mounting optics and other ancillary devices, and a MIL-STD-1913 “Picatinny railed” flat-top upper receiver.

The M16A4 has adjustable rear aperture sights integrated into the Picatinny rail-mounted carry handle assembly, reaching up to 600 meters (656 yards).

Additionally, military-issue rifles are equipped with a full-length quad Picatinny railed hand guard, which allows vertical grips, lasers, tactical lights, and other accessories to be attached.

The M16A4 MWS (Modular Weapon System) has various optional features such as a muzzle compensator, a heavier and/or free-floating barrel, a semi-circular reticle with a dot at the center used in the M27 IAR Squad Day Optic, and ambidextrous charging handles and bolt catch releases.

M4 Carbine

The M4 Carbine and M16 are both assault rifles used by the United States Armed Forces.

The M4 Carbine is a 14.5″ barreled select-fire assault rifle adopted by the US military in 1994, while the M16 is a full-size rifle adopted in 1964.

The M4 also has a Picatinny rail for attaching optics, while the M16 has a carry handle, which can be removed and replaced with other sighting devices.

Diemaco C7 and C8

The Diemaco C7 and C8 have updated variants of the M16 developed and used by the Canadian Forces and manufactured by Colt Canada.

Both rifles feature structural strengthening, improved handguards, and a longer stock compared to the earlier M16A2.

The rifles can be fired in either semi-automatic or select fire and have an A1 style rear sight.

They also have a Weaver rail on the upper receiver for a C79 optical sight, a trapdoor in the buttstock for easier access, and a spacer to adjust the stock length to user preference.

Diemaco uses hammer-forged barrels and, since the company was acquired by Colt, all Canadian-produced flattop upper receivers are machined to the M1913 standard.

The C7A2 has different furniture and internal improvements compared to the C7A1, while the C8 is the carbine version of the C7.

The Norwegian, Danish, Dutch, and British militaries also use these variants.

The History of the M16 Rifle

The M16 rifle is a formidable weapon, used by the US Armed Forces since the Vietnam War.

It all began in the 1950s when ArmaLite’s Eugene Stoner developed the AR-10 rifle.

It was a revolutionary design that featured a lightweight body, a detachable magazine, and a direct impingement gas system.

The US Army tested the rifle but eventually passed on it in favor of the M14.

Fast forward to the Vietnam War, and the US military was in need of a more reliable rifle to combat the guerrilla tactics of the Viet Cong.

ArmaLite had since developed the AR-15, a scaled-down version of the AR-10, and the US military saw an opportunity. They acquired the rights to the AR-15 and rebranded it as the M16.

The M16 was first issued to US troops in Vietnam in 1964, and it quickly became evident that the rifle was plagued with issues.

It was not sufficiently tested and was prone to jams and stoppages due to its aluminum alloy body and the fact that it was not properly lubricated.

The US Army initiated the M16 Rifle Review Panel in 1968 to investigate the issues surrounding the M16, and it resulted in the adoption of several improvements to the rifle. These included a heavier barrel, an improved bolt, and a chrome-plated chamber and bore.

In the late 1960s, Colt bought the rights to the AR-15 rifle and began producing the M16A1.

This was a marked improvement over the original design, with a heavier barrel and improved sights. The A1 was the standard service rifle for the US Armed Forces for nearly two decades, until the introduction of the M16A2 in the 1980s.

The A2 featured an improved barrel and a three-round burst capability.

It was the first M16 to feature a built-in forward assist and a modified rear sight. The A2 was eventually replaced by the M16A3 and A4, both of which featured improved furniture and a Picatinny rail for mounting accessories.

Today, the M16 is still widely used by the US Armed Forces and, in its many variations, is used by militaries all over the world.

It has evolved over the years and is now lighter, more reliable, and more accurate than ever before. It is a testament to the ingenuity of its designers and a testament to its ability to adapt and evolve with the times.

Features of the M16 Rifle

Here are some of the top features that the M16 created and revolutionized in its day.


The M16 and M16A2 rifles use a variety of magazines for their rounds. The two most common types are the Vietnam War-era 20-round magazine and the current NATO 30-round magazine.

Both are made of pressed/stamped aluminum, but the 30-round magazine is larger and sturdier to reduce in-field failure rates.

The 20-round magazine is shorter and lighter, but it is prone to tilting and jamming due to a rocking magazine follower, modern 20 round magazines have fixed this issue.

In addition to the standard USGI magazines, there are several non-U.S. and commercial magazines available, such as an all-stainless-steel magazine and Magpul’s polymer P-MAG.


The bolt carrier group is responsible for housing the bolt, which houses the firing pin and extractor.

It is the part of the rifle that cycles the rounds, and it is an integral part of how the rifle functions. The bolt carrier group is available in a variety of options and finishes, but the mil-spec version for the A2 build is the M16 full auto BCG with a phosphate coating.

This BCG is usually more expensive than other options, such as the PSA M16 5.56 Bolt Carrier Group, which is a less expensive alternative.

The M16 is a rotating bolt rifle with a gas-operated direct impingement firing action.


The M16 and M16A2 rifles both use a 20-inch barrel for optimum performance with the .223/5.56 round.

The M16 has a lightweight barrel with a 1:12 twist rate, while the M16A2 has a heavy “HBAR” barrel with a 1:7 twist rate.

The M16A1 also has a triangular handguard with polymer round handguards that are secured by triangular caps.

Both rifles have a barrel nut, and the M16A2 also has a barrel indexing pin.

Flash suppressor

The flash suppressor on the M16 and M16A2 rifles is designed to reduce muzzle flash, preserve the shooter’s night vision, reduce muzzle climb, and prevent dust from rising when the rifle is fired in the prone position.

The initial flash suppressor had three tines or prongs and was designed to disrupt the flash.

To avoid breakage and entanglement in vegetation, the design was changed to close the end, becoming known as the “A1” or “birdcage” flash suppressor on the M16A1.

On the M16A2 version of the rifle, the bottom port was closed to further reduce the muzzle flash.

The U.S. military declared the A2 flash suppressor as a compensator or a muzzle brake, commonly referred to as the “GI” or “A2” flash suppressor.


The receiver of the M16 rifle features an interchangeable complete upper receiver assembly, with various barrel lengths and profiles ranging from 7 to 24 inches long, slim and heavy, and in dozens of rifle and pistol calibers.

It also has a fully ambidextrous lower receiver, free-floating barrel and lengthened upper rail.


One of the most constant controls of the M16 series is the safety. The position and style of the safety have held nearly the same through the development of the civilian AR-15.

It’s located on the left side of the gun and can be used with a simple flick of the thumb.

Charging Handle

The charging handle on the M16 rifle is a component that is used to load and unload the rifle’s chamber.

If you are familiar with the AR-15 rifle then you are familiar with a charging handle.

The biggest difference is the charging handle is located within the rifle’s carrying handle, the charging handle is an ambidextrous component that is manipulated by the shooter to pull back on the bolt and chamber a round or eject an unfired round from the firearm.

The charging handle is also used to lock and unlock the bolt carrier group when the operator needs to access and clean the firearm’s internals. The charging handle’s robust design ensures that it can withstand the wear and tear associated with frequent use.

In my experience, the charging handle grips are smaller on the M16 clones to be more true to form than I’m used to with modern large charging handles.


The M16 can be fitted with a variety of sights, including iron sights, red dot sights, holographic sights, magnifiers, and scopes.

Iron sights are the most basic and affordable type of sights typically used on the M16 and are a core fixture of the gun on the series.

They are comprised of a front post and a rear aperture, which provides the shooter with a basic sight picture.

M16’s are known for having a fixed “A2” stlye front post that cannot be removed because the gas box is apart of the front post and the gas tube is pinned to the front post.

Red dot sights, such as the Aimpoint M4 or EOTech sights, allow shooters to quickly acquire targets and are commonly used in close-quarters or close-range combat scenarios.

Holographic sights, such as the EOtech 552 or 551, provide a wide field of view and are well-suited for fast-moving targets.

Magnifiers, such as the Aimpoint 3x, can be used in conjunction with a red dot sight to provide enhanced zoom capabilities.

Depending on the model of the rifle it may be hard to mount a red dot or other scopes due to handle. If the model you have has a removable handle you may be in luck.


The M16 is offered in a number of different stock varieties.

The original M16 stock was fixed and it wasn’t until later versions that a collapsible and removable stock was developed, which makes it easier to transport and store.

Both stocks offer exceptional durability, but with the fixed stock offers a more traditional look.

The M16A2 also requires additional components such as a rifle buffer, buffer spring, and buffer spring tube, which can all be found in one kit from Brownells.


The M16 is one of the most iconic firearms in modern history, and shoots one of the United States’ most popular cartridges, largely due to the popularity of the AR-15 a version of sorts of the M16.

The M16 fires the 5.56x45mm NATO round, while the M16A2 fires the 5.56x45mm NATO round also known as .223 Remington.

The 5.56x45mm NATO cartridge has a shorter case than the 7.62x51mm NATO round and is designed to produce lower recoil and muzzle velocity.


What is the history of the M16 rifle?

The M16 rifle was first developed in 1956 by the U.S. military in response to the Russian AK-47.

It was designed to increase firepower and dependability and eventually replaced the M14 as the U.S. standard service rifle in 1969.

However, due to bullet design, firing modes, and structural reliability, the M16 required several iterations before its adoption.

In 1971, the U.S. Army began a competition to replace the M16 Rifle with a carbine design that featured a shorter barrel for close-quarter combat.

After presenting several designs, the Army took over the M4 Carbine development in 2009 and suggested changes in materials and firing action, replacing the impingement mode (like the M16) with a solely gas-operated mode.

This led to the development of the M16A2 rifle which featured a longer barrel, improved accuracy and a three-round burst trigger.

Since then, the M4 Carbine, which is based on the M16A2, has become the standard firearm for U.S. forces in close-quarter combat and is still in widespread use today.

What type of ammunition is used in the M16 and M16A2 rifles?

The M16 and M16A2 rifles use 5.56mm (.223 cal.) cartridges in 20- or 30-round magazines.

The M16A2 can fire all NATO standard 5.56mm ammunition and can fire 40mm grenades when equipped with the M203 Grenade Launcher.

The M16A2 has a heavier barrel with a 1 in 7 twist to fire NATO standard SS 109 type (M855) ammunition.

This ammunition further increases the effective range and penetration of the rifle cartridge.

How accurate and reliable are the M16 rifles?

The M16 rifle is a highly accurate and reliable weapon. With light recoil, high velocity, and flat trajectory, they are capable of taking shots out to 300 meters with the M193 cartridge and 600 meters.

How does the M16 compare to other firearms?

The M16 rifle compares favorably to other firearms due to its lightweight design, adjustable rear sights, and ability to fire both semi-automatic and automatic fire.

They are light and work well after years of testing and combat situations. The design has been refined over time and the current Cilivan version of the M16 goes by the original name from Stoner “AR-15”.

What type of modifications have been made to the M16 rifle?

The M16 has undergone numerous modifications. The M16A1 featured a closed “birdcage” flash hider to replace the XM16E1’s three-pronged flash hider, a full fence around the magazine release to prevent accidental ejection, and a chrome plated chamber – later fully lined bore – to reduce fouling.

The bolt was also changed so the cam pin could not be inserted with the bolt installed backward, which would cause failures to eject until corrected.

The front pivot point is also strengthened, giving the area in front of the magazine well a slightly different shape.

The M16A2 addressed the problem of the A1’s “pencil” barrel tending to overheat by thickening the segment of the barrel that protrudes beyond the front sight.

Additionally, it replaced the original muzzle device with a “birdcage” compensator to help reduce muzzle climb while still diminishing flash and to eliminate the issue of excessive dirt when shooting in the prone position.

The rifling of the barrel was adjusted to a 1:7 twist rate, which helped stabilize the 5.56x45mm NATO standard ammunition.

A fully adjustable rear sight, a spent casing deflector, and a strengthened buttstock with rounded handguards were also added.

Finally, the selector switch was changed from semi-automatic and fully automatic fire to three-round burst.

What type of recoil does the M16 and M16A2 rifles generate?

The M16 and M16A2 rifles generate a straight-line recoil, where the recoil spring is located in the stock directly behind the action, and serves the dual function of operating spring and recoil buffer.

This allows recoil forces to drive straight to the rear and reduces the weight of moving parts while also reducing muzzle rise, especially during automatic fire.

As a result, follow-up shots are faster and user fatigue is reduced.

What type of muzzle device is used on the M16 and M16A2 rifles?

The M16 and M16A2 rifles use a muzzle device, such as a flash suppressor or sound suppressor, with a 1⁄2-28″ thread pattern.

The original flash suppressor had three prongs designed to preserve the shooter’s night vision, but it was prone to breakage.

The design was later changed to the “A1” or “birdcage” flash suppressor on the M16A1.

The M16A2 version of the rifle has the bottom port closed to reduce muzzle climb and prevent dust from rising.

This is known as the “GI” or “A2” flash suppressor and is classified as a compensator or a muzzle brake.

Other flash suppressors developed for the M16 include the Phantom Flash Suppressor by Yankee Hill Machine (YHM) and the KX-3 by Noveske Rifleworks.

The threaded barrel also allows the installation of sound suppressors with the same thread pattern.

What is the maximum range of the M16 rifle?

The maximum range of the M16 and M16A2 rifles is 3,000 yards (2,700 meters).

The effective range of the M16 is up to 500 yards (460 meters), while the M16A2 has an effective range of up to 600 yards (550 meters).

The horizontal range of the M16 is 711 yards (650 m) and the lethal range is 984 yards (900 m).

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