7.62x39 vs. 300 Blackout: Intermediate .30 Caliber Cartridges Collide

By Chris Dwulet

Last Updated: Mar 17, 2026

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Chris Dwulet

Chris Dwulet grew up in the heart of the Midwest (Indiana, to be precise, a storied land which gave the world both the machine gun and the mechanical corn picker, thus solving two of mankind’s greatest age-old problems). He received his first experience with firearms in his grandfather’s backyard, where he learned to handle a Remington Model 541 with astounding deftness.

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The 300 AAC Blackout and 7.62x39mm Soviet are two centerfire rifle cartridges that are extremely similar in terms of external ballistics and terminal performance.

The 7.62x39 has been a mainstay for former Communist Bloc countries for decades, and has proven its combat effectiveness on the battlefield time and time again. However, integrating the 7.62x39 into the American AR platform has been fraught with difficulty, as the cartridge does not function well with AR-15 magazines.

Despite these difficulties, shooters yearned for an intermediate .30 caliber cartridge that could bridge the gap between the 5.56 NATO and 308 Winchester in their AR-15s.

300 AAC Blackout ammo is that bridge. There’s no denying that the 300 Blackout closely mimics the 7.62x39, but there are differences between the two cartridges that make some shooters question which is right for their next sporting rifle.

In this article we will compare and contrast the 300 BLK vs 7.62x39 to help you understand the subtle nuances that make each cartridge unique – and possibly perfect for your next rifle.

What Is the Difference Between 7.62x39 and 300 Blackout?

The ballistics of 7.62x39 and 300 Blackout ammo are almost identical. The difference between them is that the 7.62x39 was developed during WWII for use in the SKS and AK-47, whereas 300 Blackout was developed in 2010 for use in a short barreled and suppressed M4 carbine. The 300 Blackout can fire supersonic and subsonic loads, while most 7.62x39 ammo is loaded for supersonic flight.

Is 7.62x39 the Same as 300 Blackout?

No. The two cartridges are completely different. They are not interchangeable.

You should never fire a round that your rifle is not chambered for. Doing so can cause a catastrophic failure that damages your firearm and injures you. Although both rifle cartridges are .30 caliber, the 7.62x39 fires a 0.311” diameter bullet while 300 Blackout fires a .308” diameter one.

Cartridge Specs

When comparing two rifle cartridges, it’s good to analyze their specs and gain more knowledge of each. For a quick visual reference, our rifle caliber chart shows how these and other popular cartridges compare in size at a glance.

One major difference between 7.62x39 and 300 Blackout are their case lengths, with the 7.62x39 having the longer of the two. This is why the 7.62x39 has a higher case capacity: 35.6gr H2O, as opposed to 26.5gr H20 for 300 BLK.

With almost 25% higher case capacity, one might assume the 7.62x39 also has a significantly higher muzzle velocity. But that’s not actually the case. When the 300 BLK and 7.62x39 are loaded with 125 grain bullets, their muzzle velocities are only around 100 fps different from one other. If you’re weighing whether to go lighter supersonic or heavier subsonic, make sure to check our guide on the best grain for 300 Blackout to match the load to your exact needs.

This is a true testament to advancements in gunpowder technology since the development of the 7.62x39. Using those advanced propellants comes at the cost of added pressure, however, which is why the 300 BLK has a max chamber pressure of 55,000 psi: almost 10,000 psi higher than SAAMI specification for 7.62x39.

Why do 7.62x39 and 300 AAC Blackout fire different bullet diameters?

One interesting thing of note is that the 7.62x39 is not a true .30 caliber bullet based on the U.S. standards of caliber measurement. The 300 BLK fires a 0.308” diameter bullet, just like the 308 Winchester (7.62x51mm NATO), 30-06 Springfield, and 300 Win Mag. However, the 7.62x39 fires a 0.311” diameter bullet.

But why, then, is the Russian ammo designated as 7.62mm caliber? This is due to a discrepancy between how Russian and American gunsmiths measure bullet caliber.

To the right lies an illustration of barrel rifling. The higher surfaces are called “lands”. The lower surfaces are called “grooves”.

Western gunsmiths use groove measurements (which are larger than land measurements) to define the caliber of a bullet. If land measurement is 7.62mm or 0.3”, then actual bullet diameter equals 0.308” (7.82mm).

To make things more confusing, Russian gunsmiths use land measurements to define bullet diameter. This means that the land measurement on an AK-47 or SKS – and therefore the true bullet diameter – will measure 0.311” (7.90mm).

Recoil

Both the 300 Blackout and 7.62x39mm are well known for having mild recoil. Most shooters will not have a problem firing either all day at the range.

As the 300 BLK has lower case capacity, it generally has less recoil than the 7.62x39.

The average supersonic 300 Blackout round has 6 foot-pounds (ft-lbs) of recoil energy. The average 7.62x39 round has 8.5 ft-lbs.

Most shooters will not have any issue handling the recoil from either rifle cartridge, as both are very mild. But for recoil sensitive marksmen, the 300 BLK will be the better choice.

Trajectory

Trajectory is how we quantify a bullet’s flight path as it travels downrange, measured in inches of bullet drop.

A flatter-shooting cartridge is preferred for shooting longer ranges, as a shooter will require fewer adjustments to their optics to compensate for bullet drop. Having a flatter trajectory also means that a cartridge will be more forgiving of ranging mistakes.

Neither the 7.62 Soviet nor 300 Blackout round is known for having an extremely flat trajectory. However, the 7.62x39 will have the better trajectory of the two.

At 400 yards, a 7.62x39 123 grain bullet exhibits about -44” of bullet drop. The 125 grain 300 BLK drops approximately -68” at the same distance.

The trajectories of these .30 caliber intermediate cartridges limit their effective ranges to around 400 yards: exactly the distance they are designed for.

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Subsonic 300 Blackout ammo makes the 7.62x39 look like it has the trajectory of a 308 Winchester! At 300 yards, a 300 BLK 220 grain bullet exhibits around -100” of bullet drop. This is not surprising. Subsonic loads are designed for close quarters combat, not long range shooting.

Ballistic Coefficient

Ballistic coefficient (BC) is a measure of how well a bullet resists wind drift and air resistance. Put another way, it’s a numeric representation of how aerodynamic a bullet is. A high BC is preferred as it indicates the bullet will buck the wind more effectively.

BC varies from bullet to bullet based on design, weight, and other factors that are beyond the scope of this article. Heavy bullets generally have higher BCs, as it takes more force to disrupt the flight of a heavier bullet than a lighter one.

The 7.62x39 has an average G1 BC of 0.270. Some of the heavier subsonic bullets for 300 Blackout have extremely high BCs, such as the Hornady 300 Blackout 208gr A-Max at 0.648. That exception aside, 300 BLK ammo usually has a BC in the ballpark of 0.350.

Although the two rounds can have similar bullet weights (123 vs 125 gr), the 300 BLK is typically loaded with bullets that are more modern and aerodyamic than those conventionally loaded in 7.62x39 ammunition.

Sectional Density

Sectional density (SD) is a measure of how well a bullet penetrates a target. This is extremely important when hunting big and medium game, where you need a bullet that can punch through thick hide, bone, and sinew.

Sectional density is calculated by comparing the bullet's weight and diameter. The higher the SD, the deeper the bullet is inclined penetrate into its target. (This is a simplified view of penetration. There are other factors to consider, such as impact velocity and termin al expansion.)

Bullet design also plays a part in penetration. A bullet designed to expand, such as a soft point (SP), Ballistic Tip, or jacketed hollow point (JHP) will probably penetrate less than a non-expanding full metal jacket (FMJ).

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Average SD for 300 BLK comes out to 0.21 while the 7.62x39 measures at 0.18. These values are virtually the sam. Indeed, it is quite possible for the two rounds' bullets to share an identical SD. i=It is unlikely that any hunter or game animal will be able to tell the difference in penetration between the two rounds.

Hunting

Although neither round was designed with hunting in mind, hunters have found both the 300 Blackout and 7.62x39 to be extremely effective on medium game at short range.

It is widely accepted that at least 1,000 ft-lbs of striking energy is required to ethically harvest a whitetail. By that standard, both rounds are effective on deer at ranges out to distances just shy of 200 yards.

Feral hog hunters commonly employ AR and AK rifles for engaging large sounders. The semi-automatic fire of either firearm facilitates the quick follow-up shots that drop many hogs quickly.

A quick note on subsonic ammunition and hunting. Subsonic loads are not typically recommended for taking medium game. Subsonic rounds simply do not have the terminal ballistics to be effective and ethical at harvesting game. Make sure you are using supersonic .300 Blackout ammo when hunting — the Hornady Black 110gr V-MAX is an excellent choice for varmint and small game.

Don't forget to stock up on your ammo! Visit our Fiocchi 300 Blackout ammo page for some affordable options!

Home Defense

There’s no denying that the 7.62x39 is an extremely effective cartridge at both short and medium engagement distances. However, when it comes to home defense, the subsonic 300 Blackout cartridge is the superior choice for one reason: over-penetration

The 7.62x39 round is well known for its ability to penetrate barriers. While this might be beneficial in wartime, it is a huge liability when it comes to home defense.

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The last thing anyone wants in a self-defense situation is to injure an innocent bystander. As you are responsible for every bullet you fire, you do not want them ending up anywhere other than inside the bad guy.

In a home defense situation, it is very likely that you’ll have neighbors nearby (unless you live in the country). As such, the 7.62’s ability to plow through barriers increases the risk of injuring an innocent bystander.

Since subsonic loads were designed for close quarters battle (CQB) and to not over-penetrate, thay are an ideal choice for hone defense. Combined with a suppressor, these rounds are completely hearing safe (no ear protection needed), which is a huge boon. Shots fired indoors are usually louder since the sound echoes off the walls.

An AR pistol or rifle with a suppressor and a mag full of subsonic 300 Blackout ammo can capably handle any home defense situation.

The 7.62x39 is an extremely capable cartridge, and will not have any problem repelling any would-be home invader. However, the potential for over-penetration with 7.62 makes subsonic 300 BLK ammo that much more appealing for home defnse.

Ammo and Rifle Cost/Availability

If you like to shoot a lot and not break the bank, then the 7.62x39 will take great care of you. As there is an ample supply of European-made steel-cased ammo on the market, the 7.62x39 is extremely affordable to fire.

When purchasing bulk FMJ ammo, it’s not hard to find 7.62x39 for about $0.36/round (at the time of writing). Premium hunting ammo from manufacturers like Nosler, Federal, Hornady and Remington typically retails for around $1.50/round and up.

Shop 7.62x39 Ammo

300 AAC Blackout is a bit more expensive, with cheap FMJ ammo typically running close to $1/round. Premium hunting and self-defense ammo typically retails for around $1.5-2/round and up.

Buying in bulk is always smart! Make sure to check out our stock of bulk 300 blackout ammo and bulk 7.62x39 ammo.

In terms of rifle availability, both cartridge have plenty of semi-automatic options available. For the 7.62x39 you’ll be looking at AK variants and surplus SKS rifles that are fairly easy to find on gun store shelves or on the secondary market. If you’re not into surplus AK rifles, then there are plenty of new production rifles available from manufacturers like Arsenal, Krebs Custom, IWI, and Palmetto State Armory.

Don't want an AK? Check out the Ruger Mini-30 which chambered in 7.62x39, or an "AR-47" made by manufacturers like CMMG and Palmetto State Armory.

Any AR-15 rifle can easily be converted to fire 300 Blackout ammo with nothing more than a barrel change. Since the 300 BLK uses the same bolt as the 223 Rem/5.56 NATO, conversion is ridiculously simple. You can even load 300 BLK ammo in a 5.56 magazine (althoguh specialized 300 BLK mags are generally more reliable).

Several bolt-action rifles chambered for either round are available to hunters. The 7.62x39 has only recently been accepted as a hunting cartridge. the CZ 527 and Ruger American Ranch are two of the better options available. Both rifles are also available chambered in 300 Blackout, and manufactures like Savage, Remington, and Howa have 300 BLK options as well.

Reloading

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If you’re into handloading, then you’re going to love the 300 Blackout. Since it shares the same caliber as and uses similar powders to the 308 Winchester, 30-06 Springfield, and 300 Win Mag (just to name a few), finding components is very simple. Brass is relatively easy to acquire. If you know what you’re doing, you can make your own 300 BLK brass out of 223 Rem cases.

Reloading allows you to customize 300 Blackout ammo to your specifications and reduce your overall cost per round.

This is not necessarily true for 7.62x39. Since steel-cased ammo is so inexpensive, it is often not cost-effective to reload 7.62x39. To further complicate matters, 0.311” diameter bullets are not as common as 0.308”, making it more difficult to find components. Brass cases are also difficult to come by for 7.62x39. Most ammo manufactures load non-reloadable steel cases.

If you plan on handloading your own ammo, the 300 Blackout is clearly the superior option.

Ballistics: 7.62 x39 vs 300 Blackout

These tables illustrate the differences – and similarities – between these two rounds' ballistic performance. While this comparison provides key performance data for both cartridges, understanding the full spectrum of 7.62x39 ballistic performance across different manufacturers, bullet weights, and barrel lengths can help you make more informed decisions about which loads work best for your specific applications. Our comprehensive 7.62x39 ballistics resource provides detailed performance data that demonstrates how this proven intermediate cartridge performs across various shooting scenarios, from hunting to target shooting to tactical applications.

7.62x39 Ballistics Chart

Note: This information comes from ammo manufacturers. Actual ballistics obtained with your firearm can vary considerably from the advertised ballistics. Also, ballistics can vary from lot to lot with the same brand and type load.

.300 Blackout Ballistics

Note: This information comes from ammo manufacturers. Actual ballistics obtained with your firearm can vary considerably from the advertised ballistics. Also, ballistics can vary from lot to lot with the same brand and type load.

For shooters who want to see how different loads perform beyond the sample data below, our comprehensive 300 Blackout ballistics resource provides detailed velocity, energy, and trajectory comparisons across multiple manufacturers and bullet weights.

A Brief History of 300 Blackout

Development of the 300 AAC Blackout (designated "300 BLK" by SAAMI) rifle cartridge began in 2010 when Robert Silvers of the Advanced Armament Corporation was approached by a member of the U.S. military.

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Some special forces units were unhappy with the stopping power that the 5.56 NATO and the 9mm (used in several SMGs) offered during close quarters combat, and wanted something that had more “oomph”. Something along the lines of the 7.62x39mm.

That same soldier had some other requirements for a hypothetical, improved rifle cartridge:

• The rounds needed to fit into STANAG standard AR-pattern mags and maintain their 30-round capacity
• The cartridge case head must be the same as 5.56mm NATO so a bolt change was not needed
• It had to fire .30 caliber projectiles and mimic the terminal performance of the 7.62x39
• The new rifle cartridge needed to be compatible with short barrel rifles (aka SBR, which has a barrel lengthunder 16”) and be completely functional with a suppressor/silencer
• Supersonic and subsonic ammo needed to be available and functional

Integrating new calibers into the AR-15 platform is nothing new to the shooting community. The 6.8 Remington Special Purpose Cartridge (SPC) and 6.5 Grendel are two examples that were mildly successful; however, they both required a new bolt, and did not satisfy the 30-round capacity requirement.

Modifying the M4 to fire 7.62x39mm was not an option, as the cartirdge's severe case angle causes multiple chambering issues using standard M4 mags. This is why you see such extreme curvature in AK mags.

Advanced Armament Corporation named its new round the "300 AAC Blackout" (aka 300 BLK, or 300 Blackout). It was approved by SAAMI on January 17th, 2011.

300 BLK bullets can be assigned to one of two weight categories, 200-220 grain subsonic, and 110 to 147 grain supersonic.

Supersonic ammo, typically firing a 125 grain bullet, has a muzzle velocity of approximately 2,250 fps and muzzle energy of around 1,400 ft-lbs. Industry standards specify the effective range of the supersonic 125 grain bullet loadings at 500 yards.

In contrast, a subsonic load firing 220 grain bullet has a muzzle velocity of around 1,000 fps and a muzzle energy of 490 ft-lbs, with an effective range of 200 yards.

These two popular loadings really illustrate the versatility of 300 Blackout ammo. With a simple magazine change, a shooter can switch from supersonic ammunition and long-range engagements to subsonic ammunition for short range combat. Better yet, the 300 BLK was designed specifically to undergo full powder burn when being fired in a 9” barrel (preferably with a suppressor/silencer).

If you’d like to learn more about how the 300 BLK compares to other cartridges, check out 300 Blackout vs 5.56 NATO and 300 Blackout vs 308 Winchester!

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A Brief History of 7.62x39

In the later stages of World War II, the Nazi regime introduced a rifle that changed the way soldiers have waged ever since.

The Sturmgewehr 44, or StG-44 for short, was a magazine-fed assault rifle capable of automatic fire utilizing lighter weight bullets. The use of an intermediate cartridge allowed the StG-44 to be controllable during automatic fire. It was also more compact than the standard battle rifles of the time, and designed to hit targets several hundred yards away.

This flew in the face of the established battle rifles of World War II. The Russian bolt-action Mosin-Nagant and American semi-auto M1 Garand could hit targets well over 500 yards away, even though most battles occurred at closer ranges. Both rifles were extremely effective. They also weighed a ton, were difficult to maneuver at close range, and had heavy recoil that made automatic fire difficult to control.

Seeing the effectiveness of the StG-44, the Soviet Union decided to develop an intermediate cartridge for its new battle rifle. It wanted this rifle cartridge to be suitable for a host of firearms, from a semi-auto carbine for close range to fully automatic machine guns for suppressive fire.

Hundreds of unique cartridge designs were submitted. The Soviets eventually settled on "57-N-231," which had cartridge dimensions of 7.62x41mm.

This new rounds bullet did boat tail, as the Soviet cartridge designers assumed (incorrectly) that a boat tail was only needed for long-range shots. The assumption that all combat would be at close range led them to this decision, as they did not expect shots to be taken at longer distance.

After extensive testing, the Soviets determined that the boat tail increased close-range accuracy as well. A new bullet with a boat tail was adopted. This longer bullet required the cartridge case to be shortened to 39mm. Thus the 7.62x39 was born.

Given the military designation "M43," the 7.62x39 was adopted for the semi-automatic SKS in 1945 and Mikhail Kalashnikov’s famous assault rifle, the AK-47, in 1949. The AK-47 became the most mass-produced military rifle in existence and the 7.62x39 has shared in its success. RPD and RPK machine guns were also chambered in 7.62x39mm.

The Russians designed 7.62x39 ammo to fire a 123 grain FMJ bullet with a muzzle velocity of 2,350 fps, 1,600 ft-lbs of muzzle energy, and a combat effective range of 400 yards. Typical bullet weights for 7.62x39 ranges between 120 to 125 grains, with 123 loadings being the most prevalent.

With the popularity of the 7.62x39 on the rise, soft point (SP) ammo has become more readily available for hunting whitetail and other medium game.

The 7.62x39 has seen combat on five continents. It is truly one of the most prevalent and combat-effective rounds to come out of the Cold War.

If you’d like to learn more about how the 7.62x39 compares to other cartridges, check out 7.62x39 vs 308, 7.62x39 vs 5.56, and 7.62x39 vs 30-30!

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Final Shots: 7.62 x39 vs 300 Blackout

The 7.62x39 and 300 AAC Blackout are two intermediate .30 caliber cartridges that will see use on the battlefield and in the woods for years to come. The terminal performance of a .30 caliber bullet has been well documented, and both rounds will deliver when it matters the most.

The 7.62x39 has stayed a force to be reckoned with since its introduction in the latter stages of World War II. It is slightly superior to the 300 Blackout in terms of muzzle velocity, kinetic energy, and trajectory. Where the 7.62 falls short is in its inflexibility. Most factory loads fire 120-125 grain bullets, which somewhat limits applications for the 7.62x39.

300 AAC Blackout is a round that truly revolutionized the AR platform, allowing shooters to fire a .30 caliber bullet from their AR-15 with merely a barrel change. The compatibility of a standard AR bolt and magazine is a huge boon to the cartridgem and allows shooters who are already invested in 5.56 NATO to fire a 7.62mm caliber bullet with minimal changes to their setups.

Which cartridge is better for you? That depends on what you want to do with your rifle.

If you’re looking for an inexpensive round to go plinking with, it’s hard to beat the 7.62x39 on the basis of cost alone. Surplus military ammo is still readily available and inexpensive, making for a fun day at the range without punching holes in your wallet.

On the other hand, if you’re looking for a cartridge that is designed for the AR-15 carbine and for use with a suppressor, then 300 Blackout is the ammo for you. Capable of firing supersonic and subsonic loads while maintaining reliability in AR barrels as short as 9”, the 300 Blackout is the ideal candidate for a suppressed AR-15 SBR.

In terms of home defense, you cannot go wrong with either cartridge. However, the 300 BLK has a slight advantage due to the availability of subsonic factory self-defense loads that will not over-penetrate as much as 7.62x39.

In the end, the 7.62x39mm and 300 Blackout are more similar than they are different. They both have their strengths and weaknesses.

Regardless of which cartridge you choose, make sure that you get all of your ammo here at Ammo.com. Fine tune your marksmanship skills until you're ready for anything!

Written by

Chris Dwulet