With the speed of sound at standard temperature at 1,126 ft/s, a bullet leaving the muzzle at a velocity greater than this will break the sound barrier and generate a bullet bow shockwave that is audible. Has anybody heard it? How loud is it?

Maybe I misunderstand your question, but I would think that every rifle caliber, with the possible exception of old ones like 45-70, would cause this. The crack you hear when a rifle is fired would be what you're talking about, right?

I know in a .22LR, they do tend to be quieter.

When I shot at 600 yards you would hear the bullet crackling down range (.308) and my friend in the pits said the crack was still uncomfortably loud. He would hear me fire over my cell phone (forgot radios) and then have time to put his phone down and cover his ears...so cool....

Regular ammo is supersonic. That's why you hear the crack when you fire - mini sonic booms.

 

You can get subsonic rounds, as well.

Regular ammo is supersonic. That's why you hear the crack when you fire - mini sonic booms.

 

You can get subsonic rounds, as well.

 

 

not all regular ammo is supersonic.

 

.45 is one of them

True true - ok Pretty much all regular ammo is

Maybe I misunderstand your question, but I would think that every rifle caliber, with the possible exception of old ones like 45-70, would cause this. The crack you hear when a rifle is fired would be what you're talking about, right?

 

 

The sound has to be a combination of the sound from the exploding powder when the bullet clears the muzzle and the sound from the bullet breaking the sound barrier. Some of the 147 gr .45 ACP rounds are 900 ft/s or so and I am wondering about the sound difference and how noticeable it is with those shots that break the sound barrier.

not all regular ammo is supersonic.

 

.45 is one of them

 

This 9MM from my Ammo Log is also subsonic. When shooting them along with some above 1,126 ft/s I could not tell the difference with the ear plugs in. I am wondering if citizens can.

 

 

Manufacturer Description Caliber Grain Bullet Category FPS Ft Lbs

Winchester Supreme Elite Ammunition Bonded PDX1 9MM 147 Jacketed Hollow Point 1000 326

subsonic pistol ammo is really intended for use with supressors, no advantage to using it in an unsupressed firearm (except for 22lr)

This is the best example I can give to you for separating the sound of impact with the report:

 

Skip to 0:30 if you are impatient

 

 

Of course, you still can't filter out the muzzle report.

 

There's just something eerie about the Thunderbolt's minigun report, it sounds like some type of demon.

just ask anyone who hs had to count crack.....bang

I have heard this many times, from bullets passing nearby or over my head and from working in the target pits in rifle matches. Each supersonic bullet makes a miniature sonic boom that is like a little "snap." It is not especially loud. You don't hear it clearly unless you are far enough away from the shooter that the bullet goes past or over you well before you hear the sound of the gun being fired.