5.56×45 vs 7.62×39 – Cartridge Comparison

For tactical rifles used for home defense or out on the range in competitions, the 5.56×45 vs 7.62×39 is a common argument among shooters and a common decision made by potential buyers. Both cartridges have a rich history of military and civilian uses and also have their loyal followings. It’s an interesting comparison with the backdrop of these two rounds often being utilized by different forces that were often pitted against one another as well.

The objective of this comparison is not to label one cartridge better than the other. What we will see is that depending on the performance category we are looking at, both of these cartridges will excel at some and perform poorer in others. What we want to do is take a look at these ballistic performance categories, compare rounds for each cartridge objectively, and in the end, draw conclusions for which is more suited for certain applications.

Every cartridge has its niche, and even two cartridges that elicit so much debate in the shooting world can reside in the same household. So, let’s first get an idea of where these two cartridges come from.

A Brief History

5.56×45mm NATO

In the late 1970’s NATO countries agreed that they needed a replacement for the 7.62x51mm round that was currently in use. The issue with the 7.62×51 was that the gun weight, ammunition weight, gun length, and recoil were all not suitable for the type of combat that was currently taking place in the world.

From this, the lighter 5.56x45mm NATO round was brought into existence. It provided a high-velocity round that had a flatter trajectory than its 7.62×51 predecessor. The lighter recoil was more tailored to semi-automatic and automatic firing in the field, and the soldier could carry the same amount or more ammunition at a much lighter weight.

This round was derived from the .223 Remington round, and contrary to popular belief is not the same as the .223. While rifles chambered for 5.56×45 NATO rounds can chamber .223 Rem cartridges, not all .223 chambered rifles can fire 5.56×45 NATO rounds because of the higher pressure generated when firing.

While the 5.56×45 NATO round is known for its military service, it is also extremely popular in civilian circles as the ever popular AR-15 is chambered for these rounds.

Ammunition is widely available and comes in a variety of bullet weights and designs to match the user’s needs. The most common bullet weights range from 50 up 75grains.

7.62x39mm

The 7.62×39 is one of the most used cartridges throughout the world. It was designed in the 1940’s in the Soviet Union to produce an intermediate cartridge that could be used in a variety of military settings. In short, an all-purpose cartridge. From its initial inception, it has undergone numerous design adjustments from then to the modern cartridge we have today.

This cartridge is often highly regarded in close quarters combat as well as in gun shooting competitions. It has recently seen a small increase in popularity in the hunting world as well. One of the most popular rifles in the world is chambered for this cartridge, the AK-47 which is an intrinsic part of the shooting world and culture.

The 7.62×39 is available with several different bullets and cartridge designs such as a full metal jacket as well as soft point bullets more suitable for hunting purposes. It is not limited to these bullet designs though and is available in a myriad of designs and jackets. The bullet weight for most 7.62×39 ammunition hangs around the 122-125 grain with some variants in the 150grain range.

Specs

 5.56x457.62x39
Bullet Diameter0.224”0.312”
Neck Diameter0.253”0.339”
Base Diameter0.377”0.447”
Case Length1.760”1.524”
Overall Length2.260”2.205”
Case Capacity28.5gr35.6gr
Max Pressure55,114psi45,010psi

For any cartridge comparison that we do, we like to take a brief look at the dimensions of the case and bullets for each cartridge. We think understanding these dimensions give you something to fall back on when looking at the performance specs. When you see the results, you have a better understanding of why the cartridge performs the way it does. When looking at the specs of these two cartridges we see some distinct differences. The first is that the 7.62×39 uses a bullet with a much wider diameter than the 5.56×45. Yes, while only wider by a tenth of an inch, that is a big difference for bullet design and has a profound effect on ballistic properties.

The 5.56×45 casing and overall cartridge is skinnier and longer than the 7.62×39. Even so, with the length of the bullets and the way they sit in the casing, the overall length between the two cartridges comes to within six-hundredths of an inch. While the 7.62×39 round can be packed with more powder than the 5.56×45 NATO, it cannot hold up to the same amounts of pressure.

To compare these two popular semi-automatic cartridges, we have selected five rounds for each cartridge that encompasses a wide range of bullet types and weights for an honest evaluation of how these two stack up to each other.

All of the rounds that we have chosen are factory loads that are available for purchase through retailers and just about anywhere that sells ammunition. We are also aware that this is still a small sample size for the number of options that are available. You might have a round you are partial to and just because it is not on this list does not mean we think it doesn’t belong or is inferior in any way. We just simply had to take into account space and clarity.

To maybe be a little more comprehensive, we actually looked at a lot of different ammunition and compiled the data. While we will not look at all of the individual rounds, because that would be a mess in graph form, we have calculated the averages from all of those rounds and will present them in each section. This increases the sample size and will also allow you to see for yourself if the rounds we have selected for comparison give a good picture of how these two cartridges stack up to each other. We have the full list of rounds used for this article at the end of the comparison. Hopefully, your favorite round is in there and you want leave us a nasty email about leaving it out.

We are also only looking at available factory loads, and omitting hand loaded rounds. While hand loading and the ballistics of hand loaded cartridges is an interesting topic, we just do not have the time to bring it into account and have omitted it from this discussion.

Below is a list of the selected rounds.

  • 5.56×45 NATO Hornady BTHP Superformance Match 75gr
  • 5.56×45 Federal American Eagle FMJ 55gr
  • 5.56×45 NATO Winchester FMJ 55gr
  • 5.56×45 NATO Hornady FMJ Black 62gr
  • 5.56×45 NATO Magtech HPBT 77gr
  • 7.62×39 Winchester Super-X 123gr
  • 7.62×39 Remington UMC Metal Case 123gr
  • 7.62x39Fusion Soft Point 123gr
  • 7.62×39 Hornady SST Steel Case 123gr
  • 7.62×39 TulAmmo FMJ 122gr

Before we get into comparing these two cartridges, we want to briefly discuss the data we are using and where it was obtained. All data within this article are computer generated. It was generated either by the manufacturer or by us through the use of ballistic calculators. When we have used a ballistic calculator, we will be sure to make clear the variables we have used.

Because it is computer-generated data, the numbers might fluctuate slightly if compared to the same rounds being measured directly from firing a rifle. This is because each rifle has its shooting profile. In fact, the data might fluctuate with the same round from rifle to rifle. Because of this, computer-generated data has an advantage that it negates these small differences between rifle platforms and it also takes environmental factors out of play.

So, in the next few sections, we will look at the 5.56×45 vs 7.62×39 through several different ballistic and performance categories including the recoil, velocity, ballistic coefficients, trajectory, energy, and sectional densities.

Recoil

Though these cartridges are becoming more prevalent in the hunting world, their main application is still in close to medium range quarters combat situations. These are a few of the favorite cartridges used in shooting competitions as well, and recoil plays a major role in being able to fire off successive shots accurately.

To compare recoil, we will look at the actual recoil force that is generated when firing a round (ft.lb). While this is not quite the “felt recoil” or the kick as it is often called, it still gives us an idea of what you will have to deal with in the field. Before we look at the recoil energy from our ten selected rounds, we want to look at a general comparison in recoil energy between the two cartridges with data provided by the ballistic calculator (Graph 1).

Average Recoil 5.56×45 vs 7.62×39

To calculate recoil energy, there are several variables that are needed. These include the muzzle velocity of the round, the powder charge, and the weight of the rifle. So we obviously have some quite a bit of influence over what the numbers are. It’s a drawback of the computer generated data route, but it also gives a good method of really comparing cartridges rather than just individual rounds.

From the first graph, we see that the 7.62×39 cartridge has a few more pounds of force generated than the 5.56×45 NATO. While this is only a small difference in recoil, it might be significant when firing several successive rounds. For single shots, neither of these cartridges are going to produce enough kick to cause flinching, at least for experienced shooters. Both of these cartridges are generating recoil less than 10ft.lb of energy.

Let’s take a look at the recoil energy that is generated from our ten selected rounds and see if this trend holds up or if we see a little more variability. This data was generated using each rounds bullet weight, muzzle velocity, gun weight (7lbs), and the powder charge. For the powder charge, we averaged several common powder loads from Nosler’s load data and kept that charge constant for each round of the same cartridge. These numbers might fluctuate slightly depending on the actual powder charge used by the manufacturer, but the trends between the cartridges should remain (Graph 2).

Recoil 5.56×45 vs 7.62×39

We do see a little variability in the amount of energy generated from round to round within the same cartridge, but overall, the trend holds up. You are going to be dealing with a few extra ft.lb of force when firing a 7.62×39 compared to a 5.56 NATO. None of the 5.56×45 rounds break the 6.2ft.lb mark while all of the 7.62×39 rounds fall within the 8-8.2ft.lb mark. Which are all numbers that we would expect from rounds that were designed to be used in semi-automatic mode.

In the table below, we have listed the recoil averages of our full list of rounds that are listed at the end of the article. We calculated this data in the exact manner that we described earlier. From the table, you can see that we are still seeing the same trends that we saw in the graphs above. There is a difference of about three and a half pounds of force between the two cartridges, which is almost exactly what we saw when looking at our selected rounds for comparison. There is definitely a difference the amount of recoil energy between these two cartridges, and from the specs we looked at earlier, it’s a difference we all could have guessed would be present.

Average Recoil (ft/lb)

5.56x45mm7.62x39mm
5.218.73

Ballistics

In this section, we will take a look at these two cartridges in the context of several ballistic categories. While ballistics alone will not tell us which cartridge performs best in specific hunting, tactical, or general shooting situations, they are a huge component. We will look at ballistic coefficients, velocity, and trajectory and use this data at the conclusion of the article to draw some conclusions for the applications of the 5.56×45 vs 7.62×39.

We think that it is also important to note that though we are looking at each of these sections individually to better compare the two cartridges, you do not get the full story from one individual category. To have a basis for your decision you have to bring all of this information together to understand which situations one cartridge or the other would be better suited. We will do our best at the end of the article to bring all this together for you.

Velocity

One of the main reasons that velocity is an important category for comparison when comparing two cartridges is because it is intricately linked to just about every other ballistic and performance spec we have and will look at. Faster rounds not only get to the target quicker, but they are also less prone to environmental factors that can slow down and throw off the trajectory and flight path of the bullet. Velocity is also critical in terminal ballistics, especially for bullet expansion and penetration.

Let’s take a look at our ten rounds and see if we can make any conclusions between these two cartridges. We will be looking at the velocity (ft/s) from the muzzle out to 500 yards. This data was compiled from the manufacturer or from ballistic calculators if the data was not present (Graph 3).

Bullet Velocity 5.56×45 vs 7.62×39

When looking at the velocity for the 5.56×45 vs 7.62×39, we see a distinct difference between the two cartridges. All rounds from the 5.56 rounds and the 7.62 rounds group together and there is a large gap between the two cartridges.

The 5.56×45, with its much lighter bullet weights and similar powder loads, gives you a much faster bullet from the muzzle out to 500 yards. These rounds have an average muzzle velocity of 3,038ft.sec and end at the 500-yard mark with an average of 1,645ft.sec. All of the 5.56×45 rounds remain at supersonic speeds throughout the 500-yard range. The 7.62×39 rounds have an average muzzle velocity of 2,352ft.sec and end at the 500-yard mark with an average of 1,123ft.sec.

While the 7.62×39 rounds have an overall lower velocity from the muzzle out to 500 yards, they do tend to hold onto their velocity better than the 5.56 where velocity bleeds off rapidly. The 7.62×39 rounds do fall below supersonic speeds at the 500-yard mark.

Let’s bring some more rounds for each cartridge into the mix and see if we see if the trend remains the same or if we see the gap close or widen.

Average Velocity (ft/sec)

Yards5.56x45mm7.62x39mm
Muzzle2989.62352.9
1002664.52048.3
20023631748.5
3002083.41520.2
4001826.91308
5001572.61144

We do all of the averages drop just a little when we bring in more rounds, but the trends that we saw all hold up. The 5.56×45 cartridge brings several hundred more ft/s of velocity than the 7.62×39 throughout the bullets flight. We also see the same trend of the 7.62×39 rounds maintaining their velocity at a better rate than the 5.56×45 rounds.

Ballistic Coefficient (BC)

The ballistic coefficient is a number that is generated from several variables related to bullet design. What this number is going to tell us is how well a bullet is streamlined. The more streamlined, the better the bullet will resist air drag and the less prone it is to wind drift. So, bullets with higher BCs maintain their velocity, force, and trajectory much better than a bullet with a lower BC. And well it doesn’t necessarily mean a more accurate bullet; it does make it easier to become accurate with it at extended distances. The BC doesn’t replace skill by any means and a high BC is not going to turn you into a Marine sniper, but it can make adjusting for long range shots a little more manageable. For these two cartridges, you’re most likely not going to be taking shots at ranges where the BC is really going to make a huge difference, but even within 500 yards in certain weather conditions, it might still be worth considering the BC in your decision.

Let’s compare the BCs of our ten rounds and see how these two cartridges differ (Graph 4).

Ballistic Coefficient 5.56×45 vs 7.62×39

All of these numbers were compiled from the manufacturer of the various rounds.

Overall, we see very similar ballistic coefficients between these two cartridges. All of them hover around the .25-.30 range. We do see that the most variability within the 5.56×45 rounds where we see two rounds with excellent BCs, a .342 and a .395, while at the same time we have the lowest BC round within the same cartridge type (.246). And this makes sense given the popularity of the 5.56×45 rounds and the more options you have with bullet types that we would see some variation in the ballistic coefficients.

Again, we should note that the BC is going to differ from round to round. While an average of all of our selected rounds is very similar, with a slight advantage for the 5.56×45 rounds, there are going to be options for both cartridges that have much higher BCs than others and you should definitely take into account what you are using these rounds for when making a decision on a cartridge type or even specific rounds.

When we look at the average BC when including more rounds, we still see that the 5.56×45 still has the slightest of advantages, but in real applications, not just looking at data, we doubt the difference would be very noticeable. The other performance specs probably deserve more attention when looking at how these two cartridges differ in performance. And of course, you are not shooting the average of the rounds, but specific ones. We do want to note though, that none of the selected 7.62×39 rounds break the 0.3 BC mark. That’s not to say that they are not out there, but there are certaintly more 5.56×45 rounds available in the +0.3 department.

Average Ballistic Coefficient

5.56x45mm7.62x39mm
0.2860.27

Trajectory

Regardless of the shooting application, the trajectory of the rounds being used is one of the first traits of a round that is examined.

What you want to look for is a flat trajectory where the bullet will travel a significant distance without losing too much elevation, which we will measure in bullet drop (inches). The more the bullet drops, the bigger the adjustments will need to be made to make an effective shot and the harder it is to be accurate on a consistent basis without a lot of od practice.

Before getting into the short and long-range trajectory, we wanted to present a graph that gives you a clear picture of how flat the trajectories of these two cartridges are (Graph 5).

Trajectory 5.56×45 vs 7.62×39

To do this, we selected a round for each cartridge that is made by the same manufacturer and uses the same bullet design with similar weights and ballistic coefficients. Selecting rounds of similar weight is near impossible with these two cartridges as we have discussed before, the 7.62 uses a higher caliber bullet than the 5.56 which often means heavier bullets.

Both of these cartridges maintain nearly the same trajectory out to the 180-yard mark. From here, we begin to see the differences between these two cartridges. The much lighter 5.56 round can maintain a much flatter trajectory than the 7.62 round and as the yardage increases so does the difference in bullet drop. By the 500 yard mark, the 7.62×39 round has dropped nearly 50 more inches than the 5.56×45 NATO round.

Let’s zoom in and look at sections of these range in more detail and see if the above trend continues.

Short Range Trajectory

For a 5.56×45 vs 7.62×39 debate, the short-range trajectory is probably a little more relevant than long-range trajectory given the applications of these cartridges.

For short-range trajectory, we are going to compare our selected rounds out to a distance of 300 yards with the test firearms zeroed in at 100 yards. We are measuring bullet drop in inches. Data was generated by compiling the numbers from the manufacturer or by a ballistics calculator. With the ballistics calculator, we determined the short range trajectory by using each rounds bullet weight, muzzle velocity, and ballistic coefficient (Graph 6).

Short Range Trajectory 5.56×45 vs 7.62×39

Leading up to the 100-yard mark we do not see any noticeable difference between these two cartridges worth mentioning. From the 100 to 200 mark, the gap does widen pretty significantly with around three inches difference between the 5.56 and 7.62 rounds averages at this range. We also see that the rounds from the two cartridges group with their respective cartridge type. The difference between the averages would be more pronounced, but you can see that the 77gr Magtech 5.56×45 round is a little steeper than the other 5.56 rounds.

The difference widens even further as the rounds move out to 300 yards. At this point, there is around 12-inch difference between the averages of the two cartridges. It is pretty clear that the 5.56×45 NATO rounds show flatter trajectories than the 7.62×39 rounds at short range. And while there is a difference, we still think both of these cartridges are effective at these ranges; you will just be adjusting more for shots taken with a 7.62×39.

Let’s take a look at the averages of these two cartridges when we use a larger sample size in the table below. The trajectories were calculated for the other rounds in the same manner that we previously stated.

Average Bullet Drop (Inches) at Short Range

Yards5.56x45mm7.62x39mm
50-0.2070.16
10000
200-3.38-6.3
300-12.86-25.2
400-30.1-58.5

We see that the larger sample size still shows the same trends as our smaller, graphed selection. All of this should make sense to us given that we are looking at two cartridges that have close to the same capacity though the 7.62×39 can hold around 7 grains more at max capacity, but with the 5.56×45 rounds having higher overall velocities, lighter bullets, and mainly higher ballistic coefficients. All of that influences the less severe bullet drop of the 5.56×45 when compared to the 7.62×39 rounds.

While this trend will most likely continue at long range trajectories, we will still take a look to see how drastic a difference it is.

Long Range Trajectory

The 7.62×39 cartridge has a bad rap when it comes to long-range shooting ability, especially when compared to the lighter 5.56×45 rounds. In this section, we will use out ten selected rounds for our 5.56×45 vs 7.62×39 comparison and see if its reputation is supported by the data.

As with the short range trajectory, we are still measuring the bullet drop in inches of our eight rounds. In this section, firearms are zeroed in at 200 yards and data points taken at 100-yard intervals out to the 500-yard mark. Data was collected and generated in the same manner as the short range trajectory (Graph 7).

Long Range Trajectory 5.56×45 vs 7.62×39

Like the short range trajectory, we again see a significant difference between cartridges with each round grouping tightly with their cartridge type. Even out to 300 yards there is a 15” difference in the average bullet drop favoring the 5.56 NATO. As the range increases so does the difference between the two cartridges. Out at 500 yards, there is at most 50″ of difference between the two. The 5.56 NATO rounds lose between 40-50″ while the 7.62×39 rounds drop 90-100″. This is a significant bullet drop for both rounds, but the 7.62×39 is much more pronounced and will be a major factor in applications for these two cartridges.

Like we have been doing, let’s take a quick look at the averages for our full selection of rounds and see if the trend holds up. In the table below, we have listed the same yard markers and also concluded more exreme distances that are hardly ever attempted seriously with these two cartridges, yet it does highlight the differences between these two cartridges well.

Average Bullet Drop (Inches) at Long Range

Yards5.56x45mm7.62x39mm
1001.753.49
20000
300-8.3-14.75
400-24.56-44.7
500-54.2-95.2
700-147.5-277
1000-487-844.5

Again, even with more samples available, the trend remains the same. The 7.62×39 rounds, on average, have about twice the amount of bullet drop than the 5.56×45 rounds. The 7.62×39 rounds also are at least or more than twice the weight of the 5.56×45 rounds so it is not very surprising.

Stopping Power

While stopping power might not be an area of concern for shooters planning on using their firearms on the range, for hunting or self-defense purposes, it is one of the most discussed categories when comparing cartridges.

There is a lot that goes into the stopping power of a specific round. In this section, we are going to focus on three factors; the kinetic energy of the bullet, the sectional density, and the bullet momentum. While there are other components such as bullet type, it doesn’t give us any useful information for comparing two cartridge types.

The three components we will discuss, all influence how a projectile will behave when it strikes a target. If you search around, you will often find a lot of arguments taking place on which

Energy

In this section, we will take a look at the energy that is associated with these rounds as they are carried down range. The force exerted on the bullet by the ignited powder and the mass of the bullet generates this kinetic energy. Once the bullets make contact with the target, this energy is transferred to the target and can cause trauma to the targets tissues and organs.

So, let’s take a look at the kinetic energy of the ten rounds we have been examining so far. This data was compiled from the manufacturer (Graph 8).

Kinetic Energy 5.56×45 vs 7.62×39

The muzzle energy shows a distinct advantage for the 7.62×39 cartridge. The 7.62×39 has an average kinetic energy of 1,525ft.lb while the 5.56×45 rounds have an average energy of 1,311ft.lb. We also see that the rounds for each cartridge groups fairly tight.

Out to the first 100 yards, the 7.62×39 rounds still have an advantage in kinetic energy (ft.lb) over the 5.56 NATO rounds though the gap between the two cartridges shrinks considerably. The heavier 75gr 5.56 round performs nearly as well, and we will see that it maintains this force much better than the 7.62 rounds.

At 200+ yards, the 7.62×39 rounds begin to bleed off their energy and are very similar to the 5.56 NATO rounds, with rounds of both cartridges falling below the 1,000ft.lb mark. Another interesting point is that from this yard marker to 500 yards, the two best performing rounds are 5.56×45 rounds.

Beyond the 300 yard mark, we no longer see the distinct trends between the two cartridges. At this point, it depends on the individual round to determine the best performance. We do still see a slight increase in the amount of energy for the 7.62 rounds at these ranges, but the difference between the two is less than 100ft.lbs.

Let’s take a look at the averages for all of our compiled rounds and see if these same trends continue.

Average Kinetic Energy (ft/lb)

Yards5.56x45mm7.62x39mm
Muzzle12511508.8
100995.41142.3
200785849.9
300613.7626.6
400474.6463.9
500348.3355.9

Again, we see the same trend between these two cartridges when we bring in more samples. From the muzzle too 100 yards, the 7.62×39 brings a pretty significant more amount of kinetic energy than the 5.56×45 rounds. And again, it is interesting to compare these two cartridges as the rounds move past the 100 yard mark. As they continue, the 7.62×39 rounds tend to loose energy at a much higher rate than the 5.56×45 rounds. From 200 yards out to 1,000 yards, there is less than 100ft.lbs difference between the two averages.

Penetration

Penetration is another factor that goes into a bullet’s stopping power. In this section, we will compare penetration from the two cartridges by looking at the sectional densities of the bullets.

The sectional density is derived from a calculation using the bullet’s weight and diameter. The jacketing and design of the bullet is also going to affect a bullets penetration. An example is a full metal jacket. A FMJ expands rapidly which is going to reduce the amount of penetration. The problem with trying to bring in bullet design is that those dame designs are used for rounds belonging to each type of cartridge, and that does not help us when trying to compare and contrast cartridges such as the 5.56×45 vs 7.62×39.

For comparison sake, we are going to limit our comparison and discussion to sectional density. We generated the sectional densities for each round using a ballistic calculator (Graph 9).

Sectional Density 5.56×45 vs 7.62×39

Interestingly, the sectional densities are pretty similar between these two cartridges.

Even though the 7.62×39 rounds use much heavier bullets, we do not see an increase in sectional densities for these rounds. On the other hand, the 5.56×45 uses much lighter bullets, but the small diameter focuses all of the force in a smaller area giving it a sectional density and similar penetration profiles to the 7.62×39 rounds.

Because of these similarities, you can’t only rely on the sectional density to give an advantage to one cartridge or the other. It’s going to depend more on individual rounds and their bullet type.
Below, we have listed the averages for the entire list of rounds we have compiled.

Average Sectional Density

5.56x45mm7.62x39mm
0.1810.182

When we add in more rounds, we still see that the sectional densities between these two cartridges are almost identical.

Momentum

The final component to stopping power that we will examine in this article is bullet momentum. Momentum, as it related to a round’s terminal ballistics, is the ability of a round to overcome resistance. From high school or college, you probably heard the definition of momentum which is the ability of an object in motion to stay in motion. Simply put, a bullet’s momentum is a good number to help understand how well it will be able to push through obstacles such as a big feral hog’s thick hide and dense shoulder bones.

There are of course other aspects of a round that plays a major role in the bullet’s performance when it comes to punching through materials, but for a discussion using computer generated data, momentum is a good indicator.

And of course, more momentum is not always needed and a decision shouldn’t be made based on what has the higher momentum.

We generated all of the data below, utilizing the bullets mass, in grains, and the velocity of the round at a given yard marker. We have graphed this data below (Graph 10).

Momentum 5.56×45 vs 7.62×39

We see from the start that the majority of the rounds from each cartridge group together with the 7.62 rounds showing quite a bit more momentum than the 5.56×45 rounds from the muzzle out to 200 yards. It is especially significant when comparing the 7.62×39 rounds to the lighter 5.56 rounds. The heavier 5.56×45 rounds (70+ grains) still show less bullet momentum, but the difference is quite a bit less. With these heavier rounds, we even see them match or even outperform (have higher) the 7.62×39 rounds once the bullets reach the more limiting distances of these rounds at 400 and 500 yards.

Let’s take a look at the average momentum for these two cartridges in the table below.

Average Bullet Momentum (lb/ft.s)

Yards5.56x45mm7.62x39mm
Muzzle26.941.2
1002435.9
20021.330.6
30018.826.5
40016.522.9
5001420

Just like in our previous discussion, we still see a much greater advantage for the 7.62×39 in bullet momentum. While the velocities are on average higher for the 5.56×45, the heavier bullet weights of the 7.62 rounds generate higher bullet momentum. And again, this alone does not mean that the 7.62×39 will be better suited for dealing with thicker protection at every occasion. While the sectional densities of the two cartridges were near identical, bullet design also has a big role to play. And as we saw when looking at the smaller selection of rounds, there are 5.56×45 rounds that do not show as large a difference from some 7.62×39 rounds as the averages would suggest, especially the heavier 5.56×45 rounds.

Accuracy

Accuracy is a tough category for trying to compare two cartridges. The best method is to take firearms chambered for either cartridge, have several different rounds and measure groupings at certain distances. The problem with doing this for an article is that a lot of other variables are in play including environmental and the skill of the one pulling the trigger. Even with a skilled marksmen, the numbers can vary from day to day.

Still, with the categories we have covered so far, we can draw a couple of conclusions when it comes to accuracy when comparing the 5.56×45 vs 7.62×39.

When looking at the velocities, the 5.56 NATO rounds show a clear advantage over the 7.62x39mm cartridge. This increased velocity, as we mentioned briefly will help keep the 5.56 rounds on path.

When we look at the trajectory, especially out past 200 yards, the 5.56 is much flatter than the 7.62×39 rounds. While the stopping power is significantly different, we are just sticking with accuracy, and less bullet drop is going to make putting a bullet on target all the easier. We see a lot of similarities with the ballistic coefficients of these two cartridges though, at least for these rounds, the 5.56×45 has rounds with higher BCs and an overall slightly higher average than the 7.62×39 rounds.

With all of that, both of these cartridges can be accurate rounds within 100 yards. Just taking a position from the numbers we have, there is not going to be any significant advantages or disadvantages between these cartridges at close range. The 7.62×39 does have slightly more recoil energy than the 5.56×45, and this could impact quick shots in succession being accurate.

Price and Availability

Both cartridges are readily available from many retailers that carry ammunition and are also available in bulk. We have listed the prices of the ten rounds we have used in our comparisons. We listed a price for 20 rounds, but you can save some money when buying these cartridges in bulk.

In today’s market, both cartridges are going to be around the same price. The 7.62×39 might be a little more expensive, but it’s not by a whole lot. And both of these cartridges have certain rounds that go for cheap and others that cost a pretty penny.

As far as options go for specific rounds of both cartridges, you will have a much wider selection of 5.56x45mm ammunition than the 7.62×39. This goes for jackets and bullet weights, and bullet designs.

AmmunitionPrice
5.56x45 NATO Hornady BTHP Superformance Match 75gr$28.47 (20 Rounds)
5.56x45 Federal American Eagle FMJ 55gr$7.99 (20 Rounds)
5.56x45 NATO Winchester FMJ 55gr$8.99 (20 Rounds)
5.56x45 NATO Hornady FMJ Black 62gr$18.33 (20 Rounds)
5.56x45 NATO Magtech HPBT 77gr$33.99 (20 Rounds)
7.62x39 Winchester Super-X 123gr$27.49 (20 Rounds)
7.62x39 Remington UMC Metal Case 123gr$19.79 (20 Rounds)
7.62x39 Fusion Soft Point 123gr$21.99 (20 Rounds)
7.62x39 Hornady SST Steel Case 123gr$47.25 (20 Rounds)
7.62x39 TulAmmo FMJ 122gr$10.99 (20 rounds)

Applications

From our experience and research, the 7.62x39mm offers a lot more options when it comes to hunting more medium sized game. The increase in bullet energy for these rounds within 100 yards is much better suited for medium sized game. The issue is the range of the cartridge. For shots within 100 yards, you have a fair shot at good bullet placement, and with the stopping power of the heavier bullets, you should be able to make a clean kill. These same regions also make it a popular cartridge for close quarters combat. If you pair the correct bullet design, you can easily punch through cover with this cartridge with power to spare.

The 5.56×45 NATO can also be used in some hunting situations for smaller game up to whitetail deer, but it has a pretty limited range because of its loss of energy downrange. With its trajectory, it is a perfect rifle for small game being taken at increased distances.

For longer range shooting, the 5.56×45 NATO offers a much flatter trajectory than the 7.62×39. For target shooting, this is a huge advantage as fewer adjustments, which gives you less chance of miscalculation, means a greater chance of landing successive shots on target.

The 7.62×39 cartridge just shows too much bullet drop to be an effective round out past the 300-yard mark. We are sure there are sects who would disagree, and those are also people with years of experience using the cartridge. In general, it’s not a great long-range option.

For ranges out to 200 yards, both of these cartridges have flat trajectories and do not need heavy adjustments to shot placement. At shorter ranges, it comes down to other performance specs when trying to select the best cartridge for you.

The 5.56×45 has much higher muzzle velocities but bleeds it off pretty quickly. On the other hand, the 7.62×39 carries greater ft.lbs of force. The greater force also means slightly more recoil than the 5.56×45. While only a few ft.lb more, after a long day of shooting, it can become apparent and even effect accuracy. Both of these cartridges are readily available and are around the same price ranges. If you’re just going out to the range for some fun, you can bulk of these two cartridges for relatively cheap.

Best Rounds

Before we wrap up this article, we want to take the ten rounds we have been using for this cartridge comparison and pick a few of them that we think are well suited for specific shooting applications.

Top Hunting Round

For hunting, we like the 123gr Fusion SP round as our pick for the 7.62×39 rounds. Like all of the 7.62×39 rounds, you are not dealing with a lot of recoil, but the main reason we have selected it for hunting is the bullet energy. Even at 200 yards, it is still carrying 907ft.lbs of energy. It also has the flattest trajectory of all the 7.62×39 rounds we examined in this article. With its energy and trajectory, it is the only round we have looked at that we would feel comfortable making a 250-yard shot.

As for the 5.56×45 round in hunting scenarios such as small to medium size game and small predators, is the 55gr Winchester FMJ. It has tremendous velocity and bullet energy. Going by loose guidelines, it has enough energy to take medium size game up to 200 yards and smaller game at even further distances. It also features one of the flattest trajectories among 5.56×45 rounds.

Top Range Round

In this section, we want to pick a single round from each cartridge type that belongs on the range.

For the 7.62×39 we like the 122gr TulAmmo FMJ. It’s not expensive and makes it a little easier to burn through a lot of rounds without wiping out your bank account. The trajectory of this round isn’t the best, and we didn’t pick it to enter into long range competitions. Mainly, we chose it for the price.

For the 5.56×45 cartridge, we like the 75gr Hornady BTHP Superformance Match round. It does generate slightly higher recoil energy than the other 5.56×45 rounds but not enough to hurt accuracy in any way. It features a high ballistic coefficient (.395) and incredible velocities and the long-range trajectory to move out to long range shots of 400 to 500 yards. The drawback to this round is it is a bit more expensive than other 5.56 rounds, but you get better ballistic performance.

Conclusion

When comparing the 5.56×45 vs 7.62×39, it’s too often we see two sides of the argument unwilling to be swayed or be open to the benefits of the other cartridge. Both of these cartridges are steeped in history, and both of them offer numerous advantages.

Too often shooters neglect a cartridge out of some form of loyalty to what they normally shoot. We hope that this article has made clear that both of these cartridges can be effective when used in the correct situation. There is no law to having rifles chambered for both and in doing so, you greatly open up your shooting world to new opportunities.

Ammunition List

5.56x45mm Nato
  • Winchester Match BTHP 77gr
  • Winchester FMJ 55gr
  • Hornady Black FMJ 62gr
  • Hornady Superformance GMX 55gr
  • Hornady Frontier BTHP Match 62gr
  • Hornady Black InterLock 75gr
  • Federal American Eagle FMJ Boat Tail 55gr
  • Federal American Eagle FMJ 62gr
  • Magtech FMJ 62gr
  • Magtech Hollow Point Boat Tail 77gr
  • Barnes VOR-TX TSX BT 70gr
  • Barnes Range AR Zinc Flat Base 52gr
  • PMC X-TAC FMJ BT 55gr
  • Barnes VOR-TX TSX BT 62gr
  • Hornady Superformance Match BTHP 75gr
7.62x39mm
  • Winchester FMJ 123gr
  • Winchester Super-X Power Point 123gr
  • Winchester PDX1 Defender Split Core Hollow Point 120gr
  • Hornady Custom SST 123gr
  • Hornady Black SST 123gr
  • Federal American Eagle FMJ 124gr
  • Federal Fusion Soft Point 123gr
  • Federal Power-Shok Jacketed Soft Point 123gr
  • PMC Bronze FMJ 123gr
  • PPU FMJ 123gr
  • PPU SPRN 123gr
  • PPU Pointed Soft Point 123gr
Huston Author Pic

Huston is a hunting enthusiast who believes your success in the field is directly correlated to the amount of preparation at home. With a degree in Microbiology and several years of doctoral work manipulating bacterial genes, he attempts to merge the rational and unbiased thinking of scientific research with the passions of hunting and fishing. With two decades of chasing all manner of upland game, hooved mammals, strutting gobblers, and any small game that can fit in his Dutch oven, he hopes to offer new ideas and viewpoints on hunting and firearm concepts and traditions.

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Pat Dominic
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Pat Dominic

Outstanding fact based article for comparative analysis. I was looking for an increase in stopping power from my 5.56 AR 15 round to one chambered in 7.62, without a significant decrease in accuracy at 100 yds. for the purpose of hog hunting in Texas. Thank You.

Mike Tanner
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Mike Tanner

Take a look at the CMMG MK47. It is a AR platform that shoot the 7.62×39 and even uses standard AK-47 magazines. A really accurate rifle and a terror on hogs out to 200 yards.

David Johnson
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David Johnson

I am buying the .223. I have used the .223 for years. Never owned one personally.
I have been shot at by people using 7.62x39s.

J P
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J P

Excellent article! In depth data analysis, coupled with the authors derived insight, should guide all readers to slecting thier optimal cartridge.

P Knight
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P Knight

Great article with lots of facts and data!

MRad
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MRad

This has been a great read for me. I’m considering building my own AR and based on the type of recreational use I plan to use my gun for, the cartridge info is invaluable.

Thank you for the time and effort to make this so easy to read and understand.

Todd
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Todd

Well done. You also explained the importance of specific ammo for the caliber

D Bruce Smith
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D Bruce Smith

Your informative article was a joy to read. My wife and I ordered two M4 carbines in 7.62x39mm having had experience firing this caliber in the SKS platform (four of them!) After a little over fours years we have had no regrets, we use ASC 20 round magazines and the carbines work without a hiccup!

We know of people that hunt Hogs with this cartridge (SKS carbines) and it’s quite popular as they have great success with the 154 grain bullet.

Thank you for your work on this article.

Brian
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Brian

Wonderful well written article that a non-gun expert nor ballistics wiz like me, could clearly understand and grasp. I like his conclusion too, as I have both an AR-15 and a AK-47. Thanks! I learned much.