in reality the difference is much bigger but gets distorted by adaptive microphone

Published on October 30, 2025
Duration: 0:39

This video compares standard supersonic and subsonic 9mm Luger ammunition from Sellier & Bellot, demonstrating their audible differences when suppressed. It explains how suppressors work and highlights the sonic crack produced by supersonic rounds breaking the sound barrier. The demonstration uses a mixed magazine to audibly showcase the effect.

Quick Summary

Subsonic 9mm ammunition (140gr) avoids the loud 'crack' of supersonic rounds (115gr) when fired through a suppressor because it travels below the speed of sound. Suppressors work by slowing down expanding gases.

Chapters

  1. 00:00Intro: 9mm Ammo Types
  2. 00:04Suppressor Function Explained
  3. 00:21Live Fire Demo: Sound Difference

Frequently Asked Questions

What is the main audible difference between subsonic and supersonic 9mm ammunition when suppressed?

When suppressed, subsonic 9mm ammunition produces a quieter sound signature because it travels below the speed of sound, avoiding the 'crack' associated with supersonic rounds breaking the sound barrier.

How does a firearm suppressor work?

A suppressor works by containing and slowing down the rapidly expanding gases expelled from the firearm's muzzle after a shot is fired, thereby reducing the overall noise level.

What ammunition brands and types are featured in the video?

The video features Sellier & Bellot 9mm Luger ammunition, specifically standard 115gr FMJ supersonic rounds and 140gr FMJ subsonic rounds.

What suppressor and optic are shown on the handgun?

The handgun is equipped with an MFT PX9 suppressor and a Holosun red dot optic.

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