Suppressor is quiet in this heat

[turnandshoot4]

Anyone else notice? Ammo that is never subsonic is now. That is all........................

 

[Scutter01]

I don't like going out in this humidity, but now I'ma have to independently verify these ridiculous claims.

 

[Westside]

it's the humidity. The air density is way above normal this week.

 

[turnandshoot4]

I LOVE it! I might go to the range just to enjoy it.

 

[Scutter01]

With these temps and humidity, I'll have to bring a wet/dry vac for the amount of sweat that will be pouring off of me.

 

[42769vette]

i would think this tempture would increase muzzle velocity, not decrease

 

[curraheeguns]

I hate shooting in this heat also, but I have noticed the exact opposite. I have a heck of a time trying to get Federal bulk pack to stay subsonic when it is cold out.

The S.O.S. changes slightly with the atmospheric conditions.

LoveMyWoods posted a great graph of this a while back. Maybe he will post it again.

 

[turnandshoot4]

With these temps and humidity, I'll have to bring a wet/dry vac for the amount of sweat that will be pouring off of me.

I just got back from the range. I ran the suppressor wet by wringing my tshirt ino the suppressor. Who would have thought sweat was a great way to wet the suppressor!?

 

[Scutter01]

I just got back from the range. I ran the suppressor wet by wringing my tshirt ino the suppressor. Who would have thought sweat was a great way to wet the suppressor!?

Sooo....you were sweating bullets?

 

[snowman46919]

of course its quieter, it is so hot out that your suppressor is sweating making it a wetfire suppressor which we all know quiets it down a bit.

 

[tradertator]

I just got back from the range. I ran the suppressor wet by wringing my tshirt ino the suppressor. Who would have thought sweat was a great way to wet the suppressor!?

Funny. Gross, but funny.

 

[combat45acp]

I just got back from the range. I ran the suppressor wet by wringing my tshirt ino the suppressor. Who would have thought sweat was a great way to wet the suppressor!?

LOL

I was shooting for about 20 min today....all of it was in the down pour of rain we had!

 

[Jimbovia]

"I was blinded by the science"

Your question got me thinking about this, so I started doing some research.

Velocity:

It seems both increased Heat and Humidity should increase velocity (speed of a bullet) if anything, (i.e. the same cartridge with the same amount of powder, and the same weight bullet, fired on a hot day would produce higher velocities than on a cooler day.)

Why?:

· Because water vapor (a gas) is not as heavy as air (primarily nitrogen and oxygen), a bullet can travel faster through higher humidity air than lower humidity air.

· As temperature increases, case pressures will also increase.

Speed of Sound:

The likely reason for what you perceived as a subsonic type of report, is because the point (speed) at which sound is considered transonic (the speed of sound; MACH 1; etc), increases as the temperature rises, and decreases as temperature drops.

I found a conversion formula....

Calculation speed of sound in humid air and the air pressure density of water - sengpielaudio

to convert Temperature, Air Pressure, and Relative Humidity into the Speed of Sound.

I used the following site...

Metric Conversion Charts - Calculators, Unit Converter Tables

to convert Fahrenheit to Celsius, and Barometric Pressure to kPa for the formula to work. As well, I had to convert meters per second (m/s) in MPH and FPS so I could apply the number to something I can relate to. We use MPH in driving a car, and FPS in measuring bullet speed.

Here is what the conversion formula kicked out:

At 20 deg C (68 deg F), 2998 kPa and 46% Humidity for my location, the Speed of sound is 346.61 m/s (775.3MPH / 1137.1 FPS)

At 35.5 deg C (96 deg F), 2998 kPa and 46% Humidity, the speed of sound is 356.51 m/s (797.4 MPH / 1169.6 FPS)

With a 28 degree difference in temp, the speed of sound increased 32.5 FPS or 22.1 MPH.

Depending on the velocity of your particular cartridge load, you could have dropped just enough to be subsonic.

Seems pretty simple to me. As the temp rises, the same cartridge load has the potential to be subsonic, which would allow the perceived report through a suppressor to be less with the recent higher temps. I use the word potential above, as the formula and theory doesn’t take into account the temperature of the cartridge when it was fired at either temp (68 deg or 96 deg), so…take this for what its worth.

Disclaimer…I am no scientist or mathematician. I used Google to search for theory on the impact of temp and humidity on air density, and the impact of the same values on sound. With that clear, if I totally botched the explanation or theory, and some scientist type can explain it better in basic terms, PLEASE DO!

 

[DeadeyeChrista'sdad]

We noticed wrb seemed quieter than wss Thursday. Not so on Friday. Yesterday, seemed even the win subson wanted to go super from the 10/22 (this is all from the 10/22. Pistol barrel length stays subsonic even with the wrb bulk.)

 

[w2k0311]

Is anybody having any serious dope setting issues at distance? Currently working on my M14 can and that is a question I have not yet had professionally answered. Thanks

 

[Mechy]

of course its quieter, it is so hot out that your suppressor is sweating making it a wetfire suppressor which we all know quiets it down a bit.

Well that settles it

 

[Mechy]

At 20 deg C (68 deg F), 2998 kPa and 46% Humidity for my location, the Speed of sound is 346.61 m/s (775.3MPH / 1137.1 FPS)

At 35.5 deg C (96 deg F), 2998 kPa and 46% Humidity, the speed of sound is 356.51 m/s (797.4 MPH / 1169.6 FPS)

With a 28 degree difference in temp, the speed of sound increased 32.5 FPS or 22.1 MPH.

It's also worth noting that the increased relative humidity increases the speed of sound in air a bit.

 

[rvb]

· As temperature increases, case pressures will also increase.

most of the time. some times it has the opposite effect. depends on the powder.

-rvb