Gunner Asch on Fri, 26 Jul 2013 19:31:58 -0700
typed in rec.crafts.metalworking the following:

A "Silencer that works on a 4,000 FPS bullet?

--
Cheers,

John B.



Sure, It's the size of a truck muffler though. And, no help for the
"crack".

ah...actually..its no bigger than about 1.75 in diameter and about 12"
long. All a silencer does is slow down the noise as the powder
pressure wave exits the barrel. A 223 for example..doesnt have a real
big bubble of gas when it exits the barrel. Just a high pressure one

And at 50 yrds..there isnt much of a crack. However there is
significant noise as the targets melon explodes. Like dropping a
watermellon from a 3rd story window. But oddly enough...it doesnt
echo much.

science is often wierd.

Go on YouTube and watch the size of the bubble as they shoot guns
underwater. The bubble of gas is surprisingly small.

Not surprising. And IMO pretty irrelevant to the sound (pressure
level) of the gunshot.

All that bubble does is show how much gas got to produced to fill
a gun barrel. It is all about how fast that "bubble" forms behind the
bullet, before it overcomes the inertia, and the bullet starts to move
out of the way.

If memory serves - a silence/muffler "merely" allows for a volume
that the "bubble" can expand into, so that the shockwave is now below
the speed of sound before it enters the "atmosphere". In theory, you
could put a silencer on a 120 mm howitzer, thus allowing you to use it
inside city limits. If you can find a place where you can mount such
a device.
Of course, you'd still have the "crack" from a supersonic
projectiles passage.
--
pyotr filipivich
"With Age comes Wisdom. Although more often, Age travels alone."