.300 Blackout vs. 5.56 NATO: A General Comparison

What Is .300 Blackout?

.300 Blackout, also known as .300 AAC Blackout or 7.62×35mm, is a centerfire rifle cartridge designed to provide different projectile-weight and velocity options in compact rifle platforms.

Available .300 Blackout ammunition includes supersonic and subsonic loads. Supersonic options commonly use lighter bullets, while subsonic loads often feature heavier projectiles. Exact bullet weights and velocities vary by manufacturer and product.

What Is 5.56 NATO?

5.56×45mm NATO is a standardized rifle cartridge widely used in military applications and available for compatible civilian firearms. It commonly uses lighter bullets than many .300 Blackout subsonic loads.

Commercial 5.56 NATO ammunition comes in different projectile designs and bullet weights. Always review the manufacturer’s specifications to understand the characteristics of a particular load.

Key Differences Between .300 Blackout and 5.56 NATO

The main differences involve cartridge dimensions, projectile diameter, and available load configurations.

• Bullet diameter: .300 Blackout uses a larger-diameter bullet than 5.56 NATO.
• Bullet weights: Both cartridges offer multiple bullet weights, but their typical commercial offerings differ.
• Velocity options: .300 Blackout is available in both supersonic and subsonic loads, while common 5.56 NATO loads are generally supersonic.
• Cartridge design: The cases and chamber requirements differ, so the cartridges are not interchangeable.
• Firearm compatibility: A rifle must be specifically chambered and marked for the ammunition being used.

These distinctions are important when comparing specifications or researching compatible products.

.300 Blackout vs. 5.56 NATO Specifications

When comparing .300 Blackout vs. 5.56 NATO specifications, consider bullet weight, muzzle velocity, projectile construction, and the manufacturer’s testing conditions.

Velocity figures can vary depending on the load and barrel length. For that reason, published numbers should be compared using equivalent test conditions whenever possible.

Neither cartridge has a single performance profile. Different loads can produce substantially different results, even within the same caliber.

Are .300 Blackout and 5.56 NATO Interchangeable?

No. Although some rifles use similar platform designs, .300 Blackout and 5.56 NATO require different chamber specifications.

Never assume that ammunition is suitable because it fits a magazine or resembles another cartridge. Confirm the chamber marking on the firearm and follow the owner’s manual. If markings are unclear or a firearm has been modified, consult the manufacturer or a qualified gunsmith before use.

How to Compare These Rifle Cartridges

When researching .300 Blackout vs. 5.56 NATO, review the intended application, available bullet weights, projectile types, and published product specifications. Confirm firearm compatibility before purchasing ammunition, and never rely on cartridge appearance alone.

Store ammunition in a cool, dry place and avoid using cartridges that are damaged, corroded, or incorrectly identified.

Final Thoughts

.300 Blackout and 5.56 NATO serve different design requirements and offer different ammunition configurations. Comparing bullet diameter, load characteristics, and cartridge specifications provides a clearer understanding of each option. Always verify the ammunition designation against your firearm manufacturer’s requirements before use.