I Found A 5.7 That Doesn’t Suck

Published on June 20, 2025
Duration: 15:56

This review tests various 5.7x28mm loads for penetration on mild steel and performance in ballistics gel. While most loads failed to penetrate 1/8 inch steel, the SM855 and T6B succeeded. Thicker 3/16 inch steel proved too much for all tested rounds. In gel, the 36 gr GPM and 55 gr Expanding Copper Sub showed favorable performance, with the latter reaching 17 inches of penetration.

Quick Summary

The SM855 (modified 5.56 M855) and T6B were the only 5.7x28mm loads to penetrate 1/8 inch mild steel. In ballistics gel, the 40 gr FMJ reached 20 inches, while the 55 gr Expanding Copper Sub penetrated 17 inches with good expansion.

Chapters

  1. 00:00Intro: 5.7x28mm Ammo Testing
  2. 00:31Mild Steel Penetration Tests
  3. 06:08Advanced Steel Testing (3/16")
  4. 07:09Ballistics Gel Performance
  5. 15:40Conclusion & Favorites

Frequently Asked Questions

Which 5.7x28mm loads penetrated 1/8 inch mild steel?

During the testing by Banana Ballistics, only two 5.7x28mm loads managed to penetrate 1/8 inch mild steel: the SM855 (a modified 5.56 M855) and the T6B. Most other tested rounds failed to achieve penetration on this target thickness.

How did the 5.7x28mm loads perform in ballistics gel?

In ballistics gel, the standard 5.7x28mm 40 gr FMJ penetrated 20 inches. The Vanguard 55 gr Expanding Copper Sub performed well, reaching 17 inches with good expansion. High-velocity loads often fragmented or tumbled, creating large temporary cavities but limiting penetration.

What were the host's favorite 5.7x28mm loads for gel performance?

The host of Banana Ballistics identified two loads as his favorites for performance in ballistics gel: the 36 gr GPM and the 55 gr Expanding Copper Sub. These demonstrated a good balance of penetration and terminal effect.

Can 5.7x28mm penetrate thicker steel targets?

No, the testing indicated that 5.7x28mm ammunition struggles against thicker steel. Even the rounds that penetrated 1/8 inch mild steel could not penetrate 3/16 inch mild steel, though they did cause significant bulges in the plate.

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