7.62x39 vs 7.62x51

Published on December 25, 2019
Duration: 14:07

This video from InRangeTV, featuring Ian McCollum, provides an analytical and experimental comparison of 7.62x39 and 7.62x51 calibers in short-barreled rifle (SBR) configurations. The expert analysis reveals that while 7.62x51 loses significant energy in an 8.5-inch barrel, 7.62x39 remains more efficient, producing comparable or even higher energy levels from the same short barrel length, albeit with substantially less muzzle blast.

Quick Summary

InRangeTV expert Ian McCollum demonstrates that 7.62x39 is more efficient than 7.62x51 in short-barreled rifles (SBRs). While 7.62x51 loses nearly 50% of its energy in an 8.5-inch barrel, 7.62x39 retains more, producing comparable muzzle energy with less disruptive blast.

Chapters

  1. 00:00Intro: SBR Caliber Efficiency
  2. 01:48Test: 16" 7.62x51 Baseline
  3. 02:37Test: 8.5" 7.62x51 Short Barrel
  4. 04:29Test: 16" 7.62x39 Baseline
  5. 05:25Test: 8.5" 7.62x39 Short Barrel
  6. 06:41Analysis & Conclusion

Frequently Asked Questions

How does 7.62x51 perform in a short-barreled rifle (SBR)?

In an 8.5-inch barrel, 7.62x51 NATO loses nearly 50% of its muzzle energy, dropping from 2327 ft-lbs to 1235 ft-lbs. It also produces significant, disruptive muzzle blast.

Is 7.62x39 a better choice for short-barreled rifles than 7.62x51?

Based on testing, 7.62x39 is more efficient in short barrels. An 8.5-inch 7.62x39 rifle produced 1203 ft-lbs of energy, comparable to 7.62x51 from the same length, but with less blast.

What is the velocity difference between 7.62x51 and 7.62x39 in short barrels?

An 8.5-inch 7.62x51 barrel yielded 1970 FPS, while an 8.5-inch 7.62x39 barrel achieved 2099 FPS, indicating 7.62x39 can maintain higher velocity in very short configurations.

What tools are needed to test firearm ballistics?

To accurately test firearm ballistics, a chronograph such as the MagnetoSpeed V3 is essential for measuring muzzle velocity. This data is then used to calculate muzzle energy.

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