On Sun, 20 May 2012 09:48:39 -0500, "HeyBub"
wrote:

notbob wrote:
On 2012-05-20, micky wrote:
OT Are gun silencers on pistols really as effective as they show in
the movies?

I would appear not. Look at these tests:

http://tinyurl.com/6nj5lrh

....and here is a chart listing real world sound levels.

http://www.sengpielaudio.com/TableOf...sureLevels.htm

I can do a very loud fingers-under-tongue whistle that hurts most
people's ears, they typically reacting by covering their ears with
their hands, abeit too late. I've measured my whistle at 113 db. The
above chart tends to indicate that most suppressors reduce a gun's
report only to close-to-painful.

So, it would appear those movies where the silencer (suppressor is the
PC term) merely goes "pffft" are nonsense. OTOH, these are jes
commercial silencers, not very expensive ultra hi-tech military
suppressors. Also, there is sub-sonic ammunition, which will go a
long way toward reducing heard noise. I once watched a marine in full
range competition regalia shoot a precision .22 target rifle
(un-suppressed) using sub-sonic target ammo. It didn't make much more
noise than those silenced firearms one sees in the movies.

BTW, if you see a suppressor on the end of a revolver, you know it's
total bull****.


Mostly right. Much of the noise in a shot is the crack from the bullet's
sonic boom. Using sub-sonic ammunition eliminates that sound.

I don't understand this. In a sonic boom, all the sound arrives at
the same time, because the airplane, or the bullet makes some of its
sound later than other sound, but the plane or bullet is so much
closer to the listener that sound still arrives at the same time.
And that's what makes the boom.

In a subsonic plane, the sound is made all the time, and it arrives at
the listener over almost that same period of time. So you hear the
plane coming for 30 seconds or more

With a bullet, the shooter is behind the bullet. The longer the time
since the bullet was fired, the farther away from him the bullet is,
so any sound made by the bullet itself would be made later and have to
travel farther to reach the shooter.

But no one ever said that the bullet was making the sound. It 's
the exploding gas that makes the sound. For the same weight of
bullet, it must take more powder and a bigger explosion to get the
bullet to travel faster, so the noise would be louder, but only in
proportion to the speed the bullet is meant to travel. If the bullet
travels 600mph (below the speed of sound) instead of 800mph (above it)
the sound for the slower bullet should be about 6/8ths the sound for
the faster bullet. (Or maybe the square of that 36/64ths, a little
more than half) . But the speed of sound would not be a special
delimiter. Any decrease in speed would accompany a decrease in sound.

And assuming the length of the bullet is the same, a supersonic .22
caliber bullet would make less sound than a subsonic .45.

Suppression of the sound of the explosion that propels the bullet is the
domain of the silencer. A suppressor is worthless on a revolver and the bolt
will begin opening - allowing sound out - on an automatic before the rest of
the sound can reach the suppressor. Where a suppressor is most effective is
on a closed-bolt rifle.

My state, Texas, just allowed hunting with a suppressor, effective September
1st.

Whether you build your own suppressor (usually pretty easy) or buy a
commercial one, the BATF requires a $200 tax for each one.