why are ar pistols so loud?

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[ARCHIVED THREAD] - why are ar pistols so loud?

Posted: 6/16/2011 1:59:10 PM EDT

Why are ar pistols so fucken loud?
Jesus! I was shooting next to some guy teaching his little kid to shoot it and and was loud as fuck. It had the noveske pig flash hider 7-10.5" barrel didn't get a good look at it.

Posted: 6/16/2011 2:05:33 PM EDT

[#1]

Im sure barrel legnth and muzzle device are a factor.

Posted: 6/16/2011 2:07:42 PM EDT

[#2]

Pressure. Peak pressure happens when the bullet is less than a few inches down the barrel. Port pressure of a rifle is about 12,000 PSI. Muzzle about 8000 PSI. Cut that barrel down to 8" and you have 18,000 PSI muzzle pressure or more.

Posted: 6/16/2011 2:08:08 PM EDT

[#3]

Cause it didn't have a suppressor.

Posted: 6/16/2011 2:15:13 PM EDT

[#4]

Short barreled rifles are louder than their longer counterparts. I shot a mini draco pistol (maybe a 7 inch barrel) and the amount of noise was close to a 50 bmg round.

Maybe a technical person can explain the details

Posted: 6/16/2011 4:12:18 PM EDT

[#5]

everytime my friend goes to the range with his pistol everyone on the firing line stops and stares in awe at the flash/bang combo

Posted: 6/16/2011 4:20:38 PM EDT

[#6]

...gunpowder?

Posted: 6/16/2011 5:14:30 PM EDT

[#7]

As I stated, PRESSURE. Shorter barrels mean higher pressure when the bullet exits the bore. Higher pressure, louder report.

Pressure is the RED curve below.

Posted: 6/17/2011 5:16:09 AM EDT

[#8]

Quoted:
As I stated, PRESSURE. Shorter barrels mean higher pressure when the bullet exits the bore. Higher pressure, louder report.

Pressure is the RED curve below.

http://www.ar15barrels.com/gfx/223plot.gif

If the chamber pressure for a pistol is about 50K PSI and for a mid-length is about 25K PSI, does that mean that the pistol is twice as loud as the mid-length with say an A2 flash hider?

Posted: 6/17/2011 6:58:13 AM EDT

[#9]

Moving to the AR Pistols forum.

Posted: 6/17/2011 8:48:21 AM EDT

[#10]

Quoted:

Quoted:
As I stated, PRESSURE. Shorter barrels mean higher pressure when the bullet exits the bore. Higher pressure, louder report.

Pressure is the RED curve below.

http://www.ar15barrels.com/gfx/223plot.gif

If the chamber pressure for a pistol is about 50K PSI and for a mid-length is about 25K PSI, does that mean that the pistol is twice as loud as the mid-length with say an A2 flash hider?

Chamber pressure is the same for all AR-15. Port pressure is different and exit pressure is different. You'll have to define "twice as loud". Decibels are not linear. One would be better off making a comparison. For instance, is an AR pistol as loud as a Weatherby 338-378 with a muzzle break. That answer would be no.

http://www.freehearingtest.com/hia_gunfirenoise.shtml

http://www.makeitlouder.com/Decibel%20Level%20Chart.txt

Posted: 6/21/2011 8:55:23 PM EDT

[#11]

Strictly for the owner's enjoyment. It's fun watching other people try and concentrate at the range when you're shooting a combination flame thrower and cannon.

Posted: 6/22/2011 4:24:36 PM EDT

[#12]

Quoted:
Strictly for the owner's enjoyment. It's fun watching other people try and concentrate at the range when you're shooting a combination flame thrower and cannon.

I run a 7.62x39 pistol with 7.5" barrel, it's quite a bit quieter than the 5.56 pistol with 7.5" barrel.

Virtually no flash signature, and minimal report.

[ARCHIVED THREAD] - why are ar pistols so loud?

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