.300 Blackout vs 7.62x39mm: Modern Suppressed Versatility Meets Battle-Tested Power

Pro Armory Editorial Team October 1, 2025

The .300 AAC Blackout (300 BLK) has earned its place as a favorite among AR-15 users for its adaptability, especially in suppressed and short-barreled rifle (SBR) setups. It was designed to maximize energy and efficiency at close to medium range, while being compatible with existing AR platforms.

Meanwhile, the 7.62x39mm round—best known as the classic cartridge of the AK-47—has a long history of military use. Rugged, inexpensive, and powerful, it has proven itself in conflicts around the globe. Its low cost and simple function make it a go-to for budget-minded shooters and those drawn to the reliability of AK-style rifles.

So how do these two calibers stack up? Let’s dive into the key comparisons and help you decide which fits your needs and shooting style.

Ballistics and Accuracy

While both cartridges deliver effective energy within 300 yards, .300 Blackout tends to hold a slight edge in precision, particularly in AR-15 platforms.

.300 Blackout:

Designed to deliver optimal performance from short barrels, it’s highly accurate, especially with high-end subsonic or match-grade loads. Bullet weights range from 110 to 220 grains. The .300 BLK was engineered to maintain good terminal performance from shorter barrels, often as short as 7.5 inches, making it a top pick for PDW builds and SBRs.

7.62x39mm:

Standard loads use a 123-grain bullet with a velocity around 2,350 fps. Though powerful, it's less consistent in AR platforms due to magazine and chambering variances. In AK rifles, it’s reliable but often lacks the refined accuracy of modern AR-15s.

In a properly tuned AR-15, .300 BLK generally shoots tighter groups at short and mid-range distances, making it the better choice for precise tactical or hunting applications.

Suppressed Use

300 Blackout Rifle suppressed

This is where .300 BLK dominates. One of its main design goals was quiet, reliable suppressed operation.

.300 Blackout:

Offers reliable cycling with subsonic rounds (~1,000 fps) when paired with a suppressor. Supersonic loads expand its versatility. When suppressed, it’s one of the quietest centerfire rifle rounds available. This makes it ideal for law enforcement, home defense, and hog hunting in populated areas.

7.62x39mm:

Suppression is more difficult. Subsonic options exist but are rare, unreliable in semi-autos, and lack the same refinement. The AK platform, while suppressible, isn’t optimized for subsonic use and typically requires tuning.

If you prioritize quiet shooting and plan to use a suppressor, .300 BLK offers more reliable results with a wide variety of factory subsonic ammunition.

Platform Compatibility

AK 47 Rifle

Platform reliability, magazine options, and aftermarket support are critical for many shooters. Here’s how they compare:

.300 Blackout:

Drops right into any standard AR-15 with only a barrel change. Uses the same bolt carrier group and magazines. This makes caliber swaps fast and affordable, and the AR platform provides endless customization options.

7.62x39mm:

Can be used in AR platforms, but requires special magazines and sometimes modified bolts. Feeding issues are common unless using optimized components. In AK-pattern rifles, however, 7.62x39mm runs flawlessly and with iconic reliability.

For shooters who value customization, modularity, and modern accessories, .300 BLK offers unmatched compatibility within the AR ecosystem. If you prefer simple, durable operation and don’t mind fewer options, the AK/7.62x39mm setup is tried and true.

Ammo Cost and Availability

Ammo cost is often a deciding factor for high-volume shooters.

7.62x39mm:

Generally cheaper and more abundant, especially in steel-cased surplus. Import brands like Wolf, Tula, and Barnaul make it easy to stockpile for plinking and training. Expect bulk deals and consistent restocks, even during ammo shortages.

.300 Blackout:

More expensive and harder to find in bulk, especially for specialty loads. However, costs have come down as popularity has increased. While brass-cased .300 BLK can be pricey, reloading and remanufactured options help offset the difference.

For range training on a budget, 7.62x39mm wins. For mission-specific performance and suppressor use, the price of .300 BLK may be worth the investment.

Ballistics Comparison Chart

Caliber	Typical Bullet Weight	Muzzle Velocity (fps)	Muzzle Energy (ft-lbs)	Effective Range (yards)
.300 Blackout	110–220 gr	950–2,250	500–1,300	150–300
7.62x39mm	123 gr	~2,350	~1,500	200–400

Note: Ballistic performance varies based on load, barrel length, and manufacturer. Supersonic .300 BLK offers greater speed than 7.62x39mm at similar bullet weights, while subsonic .300 BLK remains unique among intermediate calibers for suppressed roles.

Final Thoughts: Which One Is Right for You?

Both .300 Blackout and 7.62x39mm bring valuable attributes to the table. Your decision should depend on your priorities:

Choose 7.62x39mm if you want low-cost ammo, proven battlefield performance, and don’t mind AK ergonomics or tuning an AR to run it. It's rugged, powerful, and a favorite among global shooters.

Choose .300 Blackout if you’re building a suppressed AR setup, want better modularity, or value flexibility between subsonic and supersonic loads. It’s the ideal cartridge for home defense, tactical use, and specialized roles.

If your goal is quiet performance, modern AR compatibility, and the ability to switch between ammo types, .300 BLK is an unbeatable choice. If you just want rugged power and affordable volume shooting, 7.62x39mm remains a workhorse you can trust.

Both .300 Blackout and 7.62x39mm bring unique strengths to the table. If you’re leaning toward .300 BLK, compare it directly with 5.56 in our head-to-head guide. If 7.62x39mm feels like the better match for your needs, our best 7.62x39 range ammo roundup will help you pick the right loads to start with.

Frequently Asked Questions (FAQs)

Can I shoot .300 Blackout in a 5.56 AR?

No. You need a barrel specifically chambered for .300 BLK. The magazines and bolt can stay the same, but firing .300 BLK in a 5.56 barrel is dangerous.

Is 7.62x39mm or .300 Blackout better for hunting?

Both can take medium game like deer or hogs. Supersonic .300 BLK offers better bullet selection for AR users, while 7.62x39mm remains effective from AKs at moderate ranges.