Quick Tip: 5.45x39mm & 5.56x45mm NATO - What's the Diff?

Published on April 13, 2020
Duration: 2:47

This video provides an expert comparison between the 5.45x39mm and 5.56x45mm NATO cartridges, detailing their historical context, ballistic performance, and terminal effects. Instruction from Caleb at Brownells highlights key differences in velocity, drop, and projectile behavior, offering valuable insights for firearm enthusiasts and tactical operators.

Quick Summary

The 5.45x39mm and 5.56x45mm NATO cartridges differ significantly in case length (39mm vs. 45mm), velocity (~2800 fps vs. ~3150 fps), and terminal ballistics. The 5.45x39mm projectile tends to tumble for wound cavity creation, while the 5.56x45mm NATO is generally a better penetrator.

Chapters

  1. 00:00Introduction & 5.45x39mm History
  2. 00:335.56x45mm NATO History
  3. 00:49Velocity Comparison
  4. 01:13Ballistic Drop
  5. 01:31Terminal Performance
  6. 02:01Case Length & Naming

Frequently Asked Questions

What are the main differences between 5.45x39mm and 5.56x45mm NATO cartridges?

The 5.45x39mm has a shorter case (39mm), lower velocity (~2800 fps), and its projectile is known for tumbling. The 5.56x45mm NATO has a longer case (45mm), higher velocity (~3150 fps), and is generally a better penetrator. Both originated in the 1970s.

How do the ballistic drops of 5.45x39mm and 5.56x45mm NATO compare?

With a 100-yard zero, the 5.45x39mm cartridge typically has a drop of around 14 inches at 300 yards. The 5.56x45mm NATO cartridge, however, shows a significantly flatter trajectory with approximately a 9-inch drop at the same distance.

What is the typical terminal performance difference between 5.45x39mm and 5.56x45mm NATO?

The 5.45x39mm projectile is designed to tumble upon impact in soft tissue, creating a larger wound cavity. In contrast, the 5.56x45mm NATO is generally optimized for penetration through barriers.

When were the 5.45x39mm and 5.56x45mm NATO cartridges introduced?

The 5.45x39mm cartridge was introduced in 1974, notably with the AK-74 rifle. The 5.56x45mm NATO, while also a product of the 1970s, is considered a newer variant and should not be confused with the older .223 Remington.

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