5.56 vs 7.62: Complete Comparison Guide [Ballistics & More]

Before we dive deep into ballistics and performance, we need to clear up a point of confusion that trips up many shooters: when people say “7.62,” they could be talking about two completely different cartridges.

The young Marine in our opening story was carrying an M16 chambered in 5.56mm NATO, facing an enemy armed with an AK-47 chambered in 7.62x39mm – a Soviet-designed intermediate cartridge. Meanwhile, his platoon sergeant’s M14 was chambered in 7.62x51mm NATO (essentially .308 Winchester) – a full-power rifle cartridge that’s nearly twice as powerful.

These are not even close to being the same round, despite the shared “7.62” designation.

This article focuses primarily on the 5.56mm NATO vs 7.62x39mm comparison – the two rounds that actually faced off during the Cold War and continue to compete in the civilian market today. This is the AK vs AR debate, the Soviet vs NATO intermediate cartridge showdown that defined modern infantry combat.

However, because search intent often conflates these comparisons, I’ll address the 7.62x51mm NATO (.308 Winchester) where relevant, particularly when discussing hunting applications and long-range performance.

The Three Cartridges Compared

Here’s a quick reference showing how all three stack up:

As you can see, the 7.62x39mm and 5.56mm NATO are both intermediate cartridges designed for similar roles – general infantry combat at moderate ranges. The 7.62x51mm NATO is a completely different beast, designed for machine guns, sniper rifles, and battle rifles where longer range and greater power are priorities.

Why the confusion? It comes down to nomenclature. The Russians designated their round by bullet diameter (7.62mm) and case length (39mm). NATO did the same for their full-power cartridge (7.62mm diameter, 51mm case). This creates the potential illusion that both are part of the same “7.62” family, when in reality they serve completely different purposes.

Throughout this article, when I reference “7.62” without qualification, I’m referring to the 7.62x39mm Soviet round – the AK-47’s cartridge and the 5.56 NATO’s true Cold War rival. When discussing the larger .308/7.62x51mm NATO, I’ll specify that explicitly.

Now that we’ve cleared that up, let’s dig into how these cartridges came to be.

7.62×39

The Second World War was, for all combatants in general but the Soviet Union in particular, a distinctly unpleasant conflict.

Like many militaries before the war, the USSR, recovering from the loss of as many as 20 million Soviets as a result of famine and unrest during the Great Depression, was reluctant to invest in upgrading small arms. As such the Soviets issued the Mosin Nagant in 7.62×54 to most of its mainline troops, with other weapons in pistol calibers — such as the PPSH variants — issued to officers and specialist troopers in various roles.

What the war demonstrated to everyone involved was the need for a cartridge that had more range than pistol-caliber firearms but offered similar levels of control. This was hard to find in older, full-power rifles designed to reach out and touch the enemy at 1,000 yards.

These new cartridges would need to be usable in close quarters but still deliver fatal kinetic energy out to moderate ranges. Additionally, there was a distinct need for a cartridge that could be used in both semi and fully automatic firearms. The Soviet answer to this was the 7.62x39mm.

Since its introduction in 1944, the 7.62×39 round has been used in a wide variety of firearms. The most iconic, the AK-47, is still in use around the world today with some estimates of 75 million AK-47s worldwide.

The AK’s simultaneous development with the semi-automatic SKS saw the cartridge find a home in Simonov’s rifle, as well as some of the main fully-automatic machine guns of the Soviet era, including the RPD belt-fed and RPK magazine fed firearms.

In terms of conflicts, the round has seen a lot of battle. Beginning with the Cold War’s Berlin Airlift, including the hot wars that took much of Asia, Africa, and Latin America, the round has been on at least one, and often both, sides of armed conflict since the 1950s.

Today, firearms chambered in 7.62×39 are available in a variety of formats. The most common for civilians in the United States would be AK and SKS pattern rifles. There are, thanks in no small part to the availability of the ammunition, an increasing number of bolt action rifles chambered in 7.62×39 as well.

With its relatively heavy pill and comparatively low muzzle velocity, the CCCP’s favorite round has found applications for home defense, but is, as evidenced by its continued use, also an extremely effective offensive and hunting caliber.

The 7.62×39 provides appropriate terminal ballistics with its hollow point and soft point ammunition, making it suitable for humanely taking down medium-sized game.

5.56x45mm NATO

On the other side of the Iron Curtain, the United States and other NATO countries took a similar lesson from the Second World War as the Soviets. The needs of combat were changing, broadly expressed in two main themes.

First, soldiers needed an intermediate round that could be used out to moderate ranges, but also functional in fully automatic applications. The second was that, for logistical simplicity, that same round should be used in as many firearms as possible.

In NATO, there were two answers to these needs, the full details of which extend well beyond the scope of this article. In short, much of NATO, including many of the European powers, standardized on the 7.62×51 NATO, giving us firearms such as the FAL and G3, which are still in military use today.

The idea of a European-developed round  and, even worse , a rifle, did not please the United States, which charged ahead with the development of the 5.56mm NATO round by-and-large on their own.

After adopting the 5.56mm in the 1960s for use in their new M15, the U.S. — thanks to their relative importance in NATO — diplomatically persuaded the other nations to adopt the round. Now, the 5.56mm has become the global standard in small arms calibers.

The lighter weight bullet of the 5.56mm means that, in general, it leaves the barrel hotter than its Soviet counterpart, knocking around 3,000 fps from a standard M4 barrel. This results in a flatter shooting round, which requires less sight adjustment and allows for effective shooting at longer distances.

In terms of conflicts, the round has seen use in every American conflict since Vietnam, where it became popular in short-range jungle fights. The U.S. has also deployed the round in Latin America, Asia, Africa, and the Middle East. In addition to the M16 and M4 series of rifles, it can also be found in the M249 light machine gun, bringing the concept of one interchangeable round for a single squad to life.

Many other countries around the world have also adopted the 5.56mm, with the British and the French as notable examples. Both have developed and deployed bullpup designs, all using interchangeable magazines.

The goal was operational flexibility: if NATO was involved in a conflict as a coalition, ammunition, magazines, and other operational facets could be shared, making it possible to keep their troops fighting.

In the U.S.firearms chambered in 5.56mm come in every shape and size imaginable, from bolt action rifles right up to belt-fed replicas of the M249. It is, in many ways, America’s fighting and hunting caliber of choice.

In terms of size, we refer to both of these cartridges by the size of their bullets in millimeters – – e.g. the 5.56x45mm and larger 7.62x39mm are measured in those dimensions.

A few notes while we’re talking about size. Often you’ll see an AR receiver marked for .223, which is the imperial equivalent of the 5.56x45mm round. However, and this is important, that does not mean that they are the same round.

SAMMI makes it clear that firearms chambered for .223 are not meant to fire 5.56×45 NATO rounds. They cannot withstand the pressure of 5.56×45 NATO ammunition, and can cause catastrophic failure if fired from the wrong weapon. Always verify that you are using the correct ammunition by comparing the head stamp on the ammunition to the caliber markings on the firearm to ensure everything is kosher.

Generally, any 7.62×39 you can find conform to the Soviet specifications, so you’ll likely not have the same problems there.

To help you understand exactly how these rounds perform, we’ve compiled comprehensive ballistics data from our range testing and manufacturer specifications. All testing was conducted with 16-inch barrels at 59°F at 500 feet elevation.

Velocity Comparison

Energy Comparison

Trajectory Comparison (100-yard Zero)

The data clearly shows the 5.56 NATO’s advantage in trajectory, with significantly less bullet drop at all ranges beyond 100 yards. At 300 yards, the 7.62x39mm drops more than twice as much as the 5.56 NATO loads. However, the 7.62x39mm maintains superior energy at the muzzle and retains more energy at extreme ranges where both rounds are approaching minimum effectiveness.

In terms of uses, both rounds have a similar purpose: a general-use round for infantry small arms. With that said, they have very different ballistic profiles.

Wind Drift Analysis

Wind is the enemy of long-range accuracy, and lighter bullets are more susceptible to wind deflection. In a ~10 mph crosswind:

At 300 yards:

• 5.56 NATO 55gr: 8.5 inches
• 5.56 NATO 62gr: 7.8 inches
• 7.62x39mm 123gr: 6.9 inches

At 500 yards:

• 5.56 NATO 55gr: 24.8 inches
• 5.56 NATO 62gr: 22.3 inches
• 7.62x39mm 123gr: 20.1 inches

The heavier 7.62x39mm bullet shows better wind resistance, though the practical difference at typical engagement ranges (under 300 yards) is minimal.

7.62x39mm Ballistics and Bullet Weight

Leaving the barrel, a 7.62×39 round will put up north of 2,000 feet per second (fps). From there, the round flies flat for approximately 100 yards, then drops rather substantially. At 300 yards — about the maximum effective combat range most soldiers will have with iron sights — the 7.62×39 will drop around 20-30 inches, depending on conditions.

With its relatively heavy pill and lower muzzle velocity, the CCCP’s favorite round has found applications for home defense, but is, as evidenced by its continued use, also an extremely effective offensive and hunting caliber.

The 7.62 pill is generally about twice the bullet weight of the 5.56mm, which means at close ranges the former hits much harder. That extra weight, however, means the round takes more energy to keep moving, and thus you’ll see much larger bullet drop measurements at longer ranges when compared to the 5.56mm.

Of course, that’s a generality. Several things can impact the ballistics of any round. Ambient conditions: wind, humidity, and altitude all matter, as they affect air density. Another major factor is barrel length. At a certain point, barrels are too short to both burn all of the powder in the cartridge and give the bullet adequate time to gain speed with the pressure behind it.

For example, a 4” barreled AK pistol will suffer ballistically when compared to a standard-length 16”-barreled AK with about four times as much barrel. There’s just more runway, so to speak.

5.56x45mm Ballistics

With the 5.56mm NATO, we have a different story. The lighter weight bullet of the 5.56mm means that, in general, it leaves the barrel hotter than its Soviet counterpart, knocking around 3,000 fps from a standard M4 barrel.

From there, the first 100 yards see almost zero drop, and at 300 yards, the 5.56mm drops around 10-15 inches, half that of the chunkier 7.62. That flatter trajectory makes up for less kinetic energy with improved range.

The 5.56mm is particularly effective at medium ranges, where its precision and reduced recoil offer significant advantages over other cartridges.

Again, those are general terms. The 5.56mm round in particular is hamstrung by barrel length and rifling twist rate. The 63 grain M855 bullet, for example, was engineered for a 20” barrel which, not surprisingly, is the length with which it achieves the greatest muzzle velocity.

Fire that same M855 out of a 10” barrel and you’re looking at velocity below 2,500 fps, which is insufficient to produce a lethal wound channel.

There’s a lot to learn with the specifics of these rounds, and going down the rabbit hole into the math can be deeply enlightening should you take the time.

While not peak CIVD prices, both remain expensive to shoot. We’d be impressed if you could find either at a reasonable price, either online or in stores. The global health, logistical, and political situations have most industries in disarray, and ammo is no exception.

If we’re talking about typical circumstances, timing seems to matter, too. In the U.S. people will often look to buy AR-15s before elections, in no small part to the fear-driven dialog that takes over the airwaves in election years.

That usually drives up the price of 5.56mm and can make 7.62 a more economical option. Similarly, 7.62 can go up if, for example, new sanctions get passed and our former Soviet friends aren’t allowed to import cheap 7.62 ammo.

The bullets themselves also make a big difference. The basic, steel-cased versions of both, normally, are your best budget option, but there isn’t as huge a difference in price between brass-cased and steel-cased 5.56 ammunition as there used to be.

If you for some reason must have the nicest, coolest-looking ammo that promises to turn your standard rifle into a heat-seeking destroyer of worlds, both the 5.56 and 7.62 are going to get mighty expensive.

Generally, it’s best to find and buy ammo when the best deals can be had — and right now, everyone is wishing they’d bought considerably more ammo in 2018.

Choosing between 5.56 NATO and 7.62x39mm isn’t about which is “better” – it’s about matching the cartridge to your specific needs. Here’s how they stack up across common applications.

Home Defense: Advantage 5.56 NATO

For protecting your home and family, the 5.56 NATO gets my vote, and it’s not particularly close. The primary reason comes down to a factor that doesn’t get enough attention in caliber debates: over-penetration.

In our barrier testing, we fired both rounds through standard residential construction – two layers of 1/2″ drywall with insulation. The 55-grain M193 5.56 NATO fragmented significantly after the first wall, tumbling and breaking apart. While it still penetrated multiple walls, energy dissipation was substantial.

The 7.62x39mm 123-grain FMJ, in contrast, punched through four walls with minimal deformation. Even soft-point hunting loads maintained dangerous energy levels through multiple barriers. When you live in an apartment, townhouse, or anywhere with neighbors in close proximity, this matters enormously.

Beyond barrier performance, the 5.56 NATO offers:

• Less recoil for faster follow-up shots – Critical in high-stress situations
• Higher capacity – Standard 30-round AR magazines vs. typically 30-round AK magazines (though capacity is similar, AR magazines are more reliable in most platforms)
• Better compatibility with defensive ammunition – More quality defensive loads available from Federal, Hornady, Speer
• Easier to suppress effectively – Better suppressor options and performance

Recommended loads for home defense:

• Federal Premium 55gr Tactical Bonded ($1.20/rd)
• Hornady 55gr TAP Urban ($1.35/rd)
• Speer Gold Dot 64gr ($1.10/rd)

The 7.62x39mm can work for home defense, particularly in rural settings where over-penetration is less concerning, but you’ll need to be selective with ammunition. Soft-point or hollow-point loads are essential – never use FMJ for defensive purposes.

Hunting: Depends on Your Game

This is where the comparison gets interesting, because the answer depends entirely on what you’re hunting.

For varmints and predators (coyotes, prairie dogs, groundhogs): The 5.56 NATO dominates. The high velocity causes impressive terminal performance on small-bodied animals. I’ve taken dozens of coyotes with 55-grain V-MAX loads, and the results are immediate and humane. The flat trajectory also makes long shots on prairie dogs at 200-300 yards entirely practical.

For deer and hogs: The 7.62x39mm is the clear winner, though with important caveats.

First, check your local regulations. Many states have minimum caliber or bullet diameter requirements for deer. The 5.56 NATO (.224″ diameter) is prohibited for deer hunting in many jurisdictions. The 7.62x39mm (.310″ diameter) typically meets minimum requirements.

Second, the 7.62x39mm isn’t a long-range deer round. I limit my shots to 150 yards, though the round is technically capable of ethical kills to 200 yards with good shot placement. Beyond that, bullet drop becomes significant and energy drops below what I’m comfortable with for deer-sized game.

In my experience hunting whitetail in Missouri, the 7.62x39mm with 123-grain soft-point ammunition has provided clean, one-shot kills with proper shot placement. Hornady’s 123-grain SST is my go-to, delivering reliable expansion and adequate penetration.

For hogs, both calibers work, but I prefer the 7.62x39mm for its better brush performance and heavier bullet. Hogs are tough animals, and the extra energy at close range makes a difference.

Recommended hunting loads:

5.56 NATO – Varmints:

• Hornady 55gr V-MAX Superformance ($1.10/rd)
• Federal Premium 55gr Nosler Ballistic Tip ($1.05/rd)

7.62x39mm – Deer/Hogs:

• Hornady 123gr SST Black ($1.20/rd)
• Federal Fusion 123gr SP ($1.15/rd)
• Winchester Power-Point 123gr SP ($0.90/rd)

Competition Shooting: Advantage 5.56 NATO

In the competitive shooting world, the 5.56 NATO is king, and it’s not even close. Whether you’re shooting 3-gun, precision rifle matches, or practical rifle competitions, the 5.56 NATO offers distinct advantages:

Recoil management: The lighter recoil allows faster transitions between targets and quicker follow-up shots. In timed competitions, this matters significantly. I can run a 5-round plate rack in about 2.5 seconds with a 5.56 AR. With a 7.62x39mm AK, I’m looking at closer to 3.5 seconds due to the increased muzzle rise between shots.

Ammunition cost: When you’re burning through 200-500 rounds per match, plus practice, cost matters. Even at current prices, 5.56 NATO remains more economical for high-volume shooting.

Platform advantages: AR-15s offer better ergonomics, easier magazine changes, and more accessory options for competition use. While you can absolutely run an AK in competition (and I’ve seen skilled shooters do it), you’re starting at a disadvantage.

The only competition niche where 7.62x39mm makes sense is in vintage military rifle matches or specific “cold war” themed competitions.

Tactical/Defensive Rifle Use: Advantage 5.56 NATO

For law enforcement, security work, or serious defensive rifle applications, the 5.56 NATO is the clear choice for most users.

Logistics: If you’re coordinating with others, 5.56 NATO is the standard. Ammunition, magazines, and parts are universally available.

Barrier performance: While the 7.62x39mm penetrates barriers better, modern 5.56 NATO barrier-blind ammunition (like Federal’s 62-grain Trophy Bonded or Hornady’s 75-grain TAP) provides adequate penetration while maintaining controlled expansion.

Effective range: Most tactical engagements occur under 100 yards, but having the capability to reach out to 300-400 yards is valuable. The 5.56 NATO’s flatter trajectory makes hits at distance more achievable.

Terminal ballistics: Modern 5.56 NATO defensive loads are devastating on soft tissue. The combination of velocity and fragmenting bullets creates significant wound channels at defensive ranges.

The 7.62x39mm can certainly serve in tactical roles – it’s done so for decades around the world – but in a Western context with readily available 5.56 NATO platforms and ammunition, it’s generally the second choice.

Range/Recreational Shooting: Personal Preference

For pure enjoyment at the range, either round works well, and your choice comes down to what you enjoy shooting.

The 5.56 NATO offers:

• Lower recoil for extended range sessions
• Better long-range accuracy potential
• More precision shooting applications

The 7.62x39mm provides:

• More satisfying “thump” when hitting steel
• Fun factor and novelty of AK/SKS platforms
• Generally cheaper surplus ammunition (when available)

I keep both in my safe because they offer different shooting experiences. The 5.56 AR is for serious practice and accuracy work. The 7.62x39mm AK is for blasting steel targets and pure fun.

An update on the classic AK-47 design, the snappily-named PSAK47, made in the USA by Palmetto State Armory, is growing in popularity amongst the AK community. It has a forged receiver, an excellent barrel, and gorgeous furniture that stays close to home with the AK mystique.

This is the rifle you want if you’re looking to take advantage of the AK in its purest form and use the 7.62 round as intended; an intermediate round for infantry combat.

The 7.62×39 cartridge also provides appropriate terminal ballistics for humanely taking down medium-sized game such as deer and feral hogs, making it a versatile choice for both combat and hunting.

This rifle is both ruggedly functional and beautiful to look at. Plus it uses standard AK magazines, has a lifetime warranty, and has a stepped-up barrel and trigger. Overall, an excellent rifle in 7.62.

Internally, this is the same as the previous rifle: an AK built in the USA, to last a lifetime, but the GF4 MOEKOV shows how far 7.632 caliber rifles have come since 1944, and the GF4 has a few compelling modern touches.

First is the looks: an all-black AK is a mean-looking firearm, and the cool factor does count for something. Second, the stock can fold flat and while still allowing it to be fired. This makes the GF4 an excellent vehicle weapon, especially when compared to the AR, which doesn’t quite have the same functionality thanks to the rear buffer tube.

Additionally, with the Magpul handguard you’ve got multiple M-lok slots to add ay accessories that fit your fancy. This means that the 7.62 can certainly be used on a contemporary fighting rifle, keeping it relevant 70 years after it was first introduced.

The RPK, a bigger brother to the AK which fires the same round, is one of the better small arms of the Cold War Period. Sadly, it’s about impossible — and extremely expensive — to buy an original PRK given they’re classified as machine guns by the good ‘ol NFA.

This recreation, imported and updated by Century, is just close enough to scratch the RPK itch. Effectively, this is an AK with a long barrel and a reinforced trunion, in addition to handle, bipod, and stock. The barrel and bipod might help a little with accuracy but are even better for laying suppressive fire (or blasting paper at the local range).

Who doesn’t have a thing for vintage (or at least vintage-looking) rifles. If you’re like many classic black rifle enthusiasts the Brownell BRN15A1 retro-rifle is the 5.56 equivalent of Huey ride. They’re nearly identical to their military counterparts — giving you a faithful reproduction of an M16A1 in terms of barrel, furniture, and (semi-auto) operation. No giggle switch unfortunately.

If you’ve wanted to know what it was like to carry an early M16 in Vietnam, this is likely as close as you’re going to get. Make sure to follow the included instructions and clean the rifle carefully! The self-cleaning myth is untrue known to make the guns jam with alarming frequency.

Like 7.62 rifles, the universe of 5.56mm firearms has seen modernizing over the last few decades. This rifle, the PA15, is a great example of that progress.

Offering the same 5.56 goodness out of a shorter, M4 profile barrel complete with a forged mil-spec 7075-T6 A3 AR upper and lower receivers, a collapsing stock and the attachment points galore, this is an evolution that takes 5.56 firearms into the 21st century.

Rifles like this one have quickly become some of, if not the, most popular rifles for home defense, hunting, and plinking. The 5.56 caliber, in particular, is often praised for its effectiveness in self defense scenarios, offering a balance of stopping power and manageable recoil.

At first glance, the Galil certainly looks like an AK, and upon closer inspection, it functions a lot like one as well. The Galil is, in effect, an Israeli-built AK in 5.56mm.

That alone makes this rifle worth a second look, but it’s also a rugged fighting rifle that served the IDF through multiple conflicts, and some folks would consider it one of the best looking rifles around today. If the ARs of the world don’t scratch your itch, or you just want something interesting and effective that’s chambered for 5.56, take a look at the Galil.

1. Small Arms Review, M14 Vs M16 in Vietnam
2. Terminal Ballistics Research, 7.62×39 (M43)
3. Digital History, The Great Depression in Global Perspective
4. WorldBank.org, Weaponominics
5. Wikipedia, Sergei Simonov
6. SAAMI, Unsafe Arms & Ammunition Datasheet
7. Small Arms Defense Journal, Barrel Length Studies in 5.56mm NATO Weapons
8. ATF, Machine Gun Transferability
9. Grasyl, Intermediate cartridge comparison
10. Palmetto State Armory, Various Rifles
11. Brownells, Various Rifles