Muzzle flash photos and sound tests. PWS FFC556 compared.

[shooter521]

As for my guess as to how loud this is compared to no muzzle device -- I think it was quieter.

If that's the case, shouldn't ATF have ruled it a sound suppressor?

[The Archangel]

If that's the case, shouldn't ATF have ruled it a sound suppressor?

It has to reduce the sound dB by a certain amount to be ruled as a sound suppressor. If I can remember correctly, it is around 4-5 dB.

[Trim2L]

If that's the case, shouldn't ATF have ruled it a sound suppressor?

Flash makes pressure which is picked up by a sounds meter but it is not louder to the human ear than the report of the gunshot.

[shooter521]

It has to reduce the sound dB by a certain amount to be ruled as a sound suppressor. If I can remember correctly, it is around 4-5 dB.

Flash makes pressure which is picked up by a sounds meter but it is not louder to the human ear than the report of the gunshot.

See, that's why I hang around this place... I learn stuff. Thanks guys!

Ever do the test with one of the Vltor muzzle devices?

I'd be interested in that one, as well.

[rsilvers]

See, that's why I hang around this place... I learn stuff. Thanks guys!

Both of those statements seem incorrect so don't just let them go into your brain as fact.

[Trim2L]

Both of those statements seem incorrect so don't just let them go into your brain as fact.

Feel free to refute the statement with actual data. Light waves do not make sound, the flash is burning gas which is creating pressure. Since sound meters actually measure pressure they pick up the added pressure of the expanding gas. Flash hiders dissipate that gas so the pressure is abated to a small extend. It is not audible to the human ear over the report of the gun shot.

[rsilvers]

How can I give actual data when you already (incorrectly) said sound meters do not measure pressure?

When I took off the flash suppressor, the shot sounded louder -- I think because the flash is like a detonation. Ears detect pressure also. I know light does not make sound. It is not the lightening that you hear, but the thunder.

[ToddG]

I have no idea whether a flash hider makes XM193 sound quieter or not.

But some simple physics: sound is vibration, not pressure, technically speaking. However, sound pressure (the amplitude of the sound wave, which is the difference between the maximum pressure of the wave and the "silent" air) is part of what determines the "loudness" of a sound as we perceive it. In humans, frequency also affects loudness because we perceive different frequencies to greater or lesser extents.

It's easy to demonstrate that pressure alone is not the same as sound. Jump in the ocean and dive down to about 30 feet. There is a lot of pressure on your ears (more than you'd notice standing in front of a loudspeaker at a rock concert) but not really much sound.

So a device which is measuring the pressure of a wave might not be giving a perfectly accurate description of the "loudness" being recorded.

[Trim2L]

How can I give actual data when you already (incorrectly) said sound meters do not measure pressure?

When I took off the flash suppressor, the shot sounded louder -- I think because the flash is like a detonation. Ears detect pressure also. I know light does not make sound. It is not the lighting that you hear, but the thunder.

The lighting in my house doesn't make thunder but I digress...sound meters measure pressure, there is nothing incorrect about it.

Here is what you posted: "It is not commonly known but flash makes noise." Light does not make sound, pressure does. The flash is not audible over the gun shot.

[SuicideHz]

How can I give actual data when you already (incorrectly) said sound meters do not measure pressure?

When I took off the flash suppressor, the shot sounded louder -- I think because the flash is like a detonation. Ears detect pressure also. I know light does not make sound. It is not the lighting that you hear, but the thunder.

Actually it's the expanding air that you hear created by being instantly heated by the lightning.

So this is all fine and dandy for R&D but can the human eye ever pick any of this stuff up? Can NV ever pick up the difference between a vortex and blackout? I'm sure it can between Vortex and A2, but between vortex and blackout? Considering the NVG these days still has random little flickers and flashes in the screen caused by errant electrons?