Do bullets make sonic booms?

All in the title.

I don’t know, but I would guess that you wouldn’t be able to distinguish the “boom” of a passing supersonic bullet from the sound of the gun firing.

Of course. Very tiny ones.

Yes, they do, but as indicated above, the bullet’s sound production is pretty minor compared to the gun’s.

Also very loud.

(I worked in a target pit at a competition one weekend just after high school.)


Bullets flying overhead that were fired from 1,000 yards sounded as if I was standing next to the rifle when it was fired.

What does it sound like? A loud crack?

Yes, absolutely. Almost all rifle bullets do except for small rounds like .22 rounds. Not all handgun bullets go supersonic but many do. I don’t think .38 or 9mm rounds go supersonic but I could be wrong about that. The magnum rounds generally go supersonic IIRC. This produces problems with silencers because you can’t silence a bullet’s sonic boom. You can only mitigate the power burn.

I always thought it was odd that some engineers basically predicted the end of the world if an airplane broke the sound barrier. Bullets proved that it could be done.

They do if they break the local speed of sound. Ever hear of the “crack” of a bullet?

Rifle bullets routinely travel faster than the speed of sound. This is why you never hear the bullet that kills you.

[sub]ETA: I need to post faster. I keep getting interrupted by actual work.[/sub]

Sure it would. The sonic boom doesn’t originate at firing, it’s a wave front that rides along the front of the object and propagates along with the object. If you take a moment in time, the shock wave front would look like a cone extending backwards; the angle is a function of the speed. The shooter wouldn’t be able to discern the difference, but somebody downrange certainly would.

My WAG, however, is that the area would be so small that the wave wouldn’t have very much energy behind it, and would attenuate pretty quickly. I’d think that if you could hear the boom from a supersonic round that you’d also be able to hear the bullet ripping through the air. I wouldn’t want to be that close to it, if it were up to me.

Sure do.

Easiest way is just to hop onto Youtube and search for silenced weapons. Even when the discharge is so quiet that you can hear the action cycling, the distinctive wak! of a sonic boom is quite noticeable.

I’d find some for you but I’m at work with no speakers.

If I recall correctly, some silencers are made to slow the bullet to subsonic speeds, but I’m not sure how effective that would be and i just remember reading it years ago, who knows how accurate the source was. I think silencers are used most frequently on pistols, and a lot (if not most) pistols fire subsonic ammunition.

If you google ‘subsonic ammo’ you’ll get many hits relating to using subsonic ammunition with suppressors(silencers) and reviews thereof.

One of the biggest drawbacks of subsonic ammo is that some weapons operate poorly because of the reduced recoil not supplying enough energy to cycle the slide to eject the spent casing and seat the next round.

Do you have a cite for that, or are you misremembering the story that some scientists thought the first atomic bomb might ignite the atmosphere?

Silencers can be useful, even on supersonic bullets. They make it difficult for someone to find the location of the shooter just by listening for the direction of the muzzle blast, which is good for the health of a sniper who is trying to remain undetected.

And then there are weapons that have a action locking feature to prevent the cycling of the action because of the sound it makes. And it also prevents the brass from being thrown.

What do you think the sonic boom is, if not “the bullet ripping through the air”?

There are some designs of weapons with built-in silencer, which have simply small holes along the barrel that let excess gases away and thus slow bullets to subsonic speeds. Of course, slower bullets means less power, so actually most modern design prefer subsonic ammo - slower but heavier.

Pistol caliber ammo is probably divided 50-50 between subsonic and supersonic, with 9mm, .357 and 10mm mostly supersonic and .45, .38 or .40 mostly subsonic (details may vary depending on load).

Silencers are more commonly used nowadays with assault rifles as well - while you can still hear that you are shot at, but it’s harder to find from where you are shot at.

If you had paper targets in the pits, the round hitting the paper has a “slap” sound also that could have overpowered the sonic snap. If you were in the pits halfway downrange, though, that was all sonic snap.

The sonic boom is the sonic boom. The “ripping through the air” is what you hear when a .22 flies past your head, or the sound a rope makes when you swing it.[/del]

ETA: You’re right; they’re forming at the same time in the same place. I was conflating subsonic ripping and supersonic ripping. At least this time when I was wrong, I put in the WAG disclaimer. :slight_smile:

I refrained from posting for lack of cite, but I do recall from high school (before internet) a story about a couple of old superstitions.

The first being that in the beginning of automobiles there were people who believed a man’s head would explode if he went faster than 60mph.

And then later their children or grandchildren held fast to the belief that a plane would destroy itself if it exceeded the speed of sound.

I don’t recall ever hearing about the a-bomb thing but it seems ‘reasonable’ that someone would imagine that. I suppose their kids and grandkids are now worrying about black holes created by the LHC near Geneva.

Someday, someone will be protesting that the warp engine will cause the sun to go nova.