In this guide, let's break down 7.62X39 vs 300 Blackout in detailed specs. Both rounds are popular ammo for personal defense, target shooting and hunting.
Here are their differences:
7.62X39 VS 300 Blackout - Key Differences
The 300 AAC Blackout and the 7.62x39mm Soviet, share many similarities in terms of external ballistics and terminal performance, but they are NOT interchangeable.
300 BLK is developed for short barrel and suppressed carbines, while 7.62X39 was developed for SKS and AK.
For decades, the 7.62x39 has been a go-to choice for former Communist Bloc countries and has repeatedly demonstrated its effectiveness in combat. However, fitting the 7.62x39 into American AR rifles has faced challenges due to compatibility issues with AR-15 magazines.
Despite these challenges, many shooters wanted an intermediate 30-caliber cartridge for their AR-15s to fill the gap between the 5.56 NATO and 308 Winchester.
This is where the 300 Blackout comes in. It's undeniable that the 300 Blackout closely resembles the 7.62x39, but there are differences between these cartridges that may make shooters question which one is best for their next sporting rifle.
7.62 vs. 300 Blackout Dimensions
7.62 X 39
7.62x39 and 300 Blackout are two different types of rifle cartridges, but they have some similarities. One of the differences is the length of the cartridge case. 7.62x39 is longer than 300 Blackout. This affects how much powder they can hold. 7.62x39 can hold more powder, 35.6 gr H2O, compared to 26.5 gr H20 for 300 BLK.
Referenced Larry Vickers
You might think that 7.62x39 would be faster because it holds more powder, but that's not always the case. For supersonic loads using a 125 grain bullet, there is only about a 100 fps difference between 300 BLK and 7.62.
This is because gunpowder technology has improved since 7.62x39 was made. But, the new powders have higher pressure. That's why 300 BLK is rated for 55,000 psi and 7.62x39 is rated for 45,010 psi based on SAAMI specifications.
The 5.56 also has a longer throat, which is .125 inches longer than the 223 Remington. This longer throat provides more room for gunpowder, making the 5.56 perform better than the 223.
The 223 bullet has tighter dimensions, which compensates for the pressure difference when fired from the same case. However, it has a smaller gunpowder capacity, giving it less power compared to the 5.56.
30 Cal Ballistics
The Ballistic Coefficient (BC) is a measure of a bullet's aerodynamics, indicating its ability to handle wind drift and air resistance. Heavier bullets generally have a higher BC as they are less susceptible to changes in flight path.
The 7.62x39 has an average BC of 0.27, while the 300 Blackout ammo has a BC of 0.35. However, some subsonic 300 Blackout bullets, like the 208 gr Hornady A-Max, boast a much higher BC of 0.648 due to their modern and aerodynamic design, compared to the older design of 7.62x39 projectiles.
7.62X39 VS 300 Blackout Cost
For budget-friendly target shooting, the 7.62x39 is the better choice. Its ample supply of European steel cased ammo makes it incredibly affordable, with bulk FMJ rounds costing around $0.36 each. On the other hand, 300 AAC Blackout is a bit more expensive if you want ultimate suppressed shooting, with cheap FMJ rounds usually priced at close to $1 each.
Both cartridges have plenty of semi-automatic options available. 7.62x39 can be found in AK variants and surplus SKS rifles, or in new production rifles from manufacturers like Arsenal, Krebs Custom, IWI, and Palmetto State Armory. If you prefer a different style, consider the Ruger Mini-30 chambered in 7.62x39 or the CMMG Mutant or PSAK-47 for an AR pattern rifle.
- Limited Projectile Selection
- Affordable centerfire round
- Steel cased ammo mostly available on the market
- FMJ ammo can be found for $0.36/round
- Extreme cartridge taper reduces reliability of AR magazines
- Hunting ammo from well-known manufacturers can cost $1.50/round and up
- Plenty of semi-automatic rifle options available (AK variants, SKS rifles, new production rifles from Arsenal, Krebs Custom, IWI, Palmetto State Armory)
- Mini-30 from Ruger and limited AR pattern options (CMMG Mutant and PSAK-47) also available
- Not cost-effective for handloading due to difficulty finding components
300 AAC Blackout:
- More expensive than 7.62x39
- FMJ ammo typically costs $1/round
- Full mag compacity in AR mags
- Hunting and self-defense ammo can cost $1.5-2/round and up
- Easy to convert AR-15 to fire 300 BLK with a barrel change
- Plenty of factory produced 300 BLK rifles available from AR-15 manufacturers
- Ruger Mini-14 Tactical also available
- Bolt action rifles available for hunting (Savage, Remington, Howa)
- Great for handloading due to easy access to components and ability to customize ammo.
- 300 Blackout is superior option for handloading
- Fires same caliber bullet and uses similar powders as 308 Winchester, 30-06 Springfield, and 300 Win Mag
- Brass is easy to acquire and can be made from 223 Rem cases
- Handloading allows customization and reduces overall cost per round
- 7.62x39 is not cost-effective for handloading due to difficulty finding components and steel cased ammo being inexpensive.
7.62X39 Ballistic Chart
Referenced The Firearm Blog
.300 Blackout Ballistic Chart
Referenced The Firearm Blog
Personal Defense Applications
For home defense, both cartridges are reliable, but the 300 BLK has an advantage with its availability of subsonic factory self-defense loads that won't over penetrate as much as the 7.62x39.
In contrast, the 300 AAC Blackout transforms the AR platform with its ability to fire 30-caliber bullets from an AR-15 with just a barrel change or an AR15 upper receiver swap. The compatibility with standard AR bolts and magazines makes it a convenient choice for shooters already invested in 5.56 NATO.
Your choice between the two cartridges depends on your intended use for your rifle. If you're on a budget, the 7.62x39 offers low-cost ammo options, such as readily available and inexpensive surplus military ammo.
But if you're looking for a cartridge designed for use with an AR-15 carbine and a suppressor, the 300 Blackout is the way to go. It can fire both supersonic and subsonic loads with reliability in barrels as short as 9 inches, making it perfect for a suppressed SBR AR-15 rifle.
7.62X39 vs 300 Effective Range
The 7.62 Soviet and 300 Blackout bullets are not known for being very flat in their trajectory. However, the 7.62x39 bullet is better in this way. At a distance of 400 yards, the 123 grain 7.62x39 bullet will have dropped about 44 inches, while the 125 grain 300 BLK bullet will have dropped about 68 inches.
When we talk about how a bullet travels through the air, we measure it with something called trajectory. This means how far the bullet drops as it goes forward.
A bullet that doesn't drop as much is better for shooting from far away. This means the shooter doesn't have to change their sights as much. It also means they are less likely to make a mistake with their aim.
These two types of bullets were made to be used at a maximum distance of 400 yards. This is why they don't have a very flat trajectory.
If you use a special type of 300 Blackout bullet called subsonic, it will have an even flatter trajectory. At 300 yards, the 220 grain 300 Blackout bullet will have dropped about 100 inches. This type of bullet is meant to be used in close-quarters fighting, not for long-range shooting.
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