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9/22/2017 12:11:25 AM
Posted: 2/21/2006 10:45:58 AM EDT


Ok so I'm a n00bie with most things regarding guns but I'm trying to learn as fast as I can. I'm just learning about the difference between supernonic and subsonic rounds.

When I shoot my WWB .45 ACP how much of the bang is from gun powder and how much is a mini sonic boom? Or is this just a silly question because I don't understand what I'm talking about?

Of maybe another way of answering this question is with a chart on decibels from super- and subsonic rounds. Anyone know of one?
Link Posted: 2/21/2006 10:52:20 AM EDT
INTERESTING........ Tag for replies
Link Posted: 2/21/2006 10:54:57 AM EDT

Depends at what altitude you're at. Georgia is about 600 ft above sea level and Iowa is 800 ft above sea level. We get more bang. Our farts and burps are much louder too.

Shok
Link Posted: 2/21/2006 10:55:20 AM EDT
I'm no expert, but I don't think you're going to hear the sonic boom unless it's reflecting off something, or the bullet is going past you. It's probably just the bang from the primer & powder.
Link Posted: 2/21/2006 10:55:36 AM EDT

Originally Posted By five2one:

Ok so I'm a n00bie with most things regarding guns but I'm trying to learn as fast as I can. I'm just learning about the difference between supernonic and subsonic rounds.

When I shoot my WWB .45 ACP how much of the bang is from gun powder and how much is a mini sonic boom? Or is this just a silly question because I don't understand what I'm talking about?

Of maybe another way of answering this question is with a chart on decibels from super- and subsonic rounds. Anyone know of one?



87 Percent.
Link Posted: 2/21/2006 10:57:06 AM EDT
Most standard .45 ACP rounds are subsonic. That means the boom you hear is the propellant explosion in the chamber.

Any thing with a muzzel velocity in feet per second that is less than the speed of sound in feet per second...won't make a sonic boom.

Because the .45 ACP round is subsonic, it lends itself very well to the use of a suppressor. All supressors can control is the propellant explosion noise. If shooting a super sonic round, a can won't stop the sonic boom.
Link Posted: 2/21/2006 10:57:49 AM EDT
Higher veloctiy rounds seem to have a sharper crack sound as apposed to just a loud bang to me. Such
as my 22-250 and hot .223 reloads in my single shot. Not really sure what to tell you tbh. Just
something I've noticed.
Link Posted: 2/21/2006 10:58:33 AM EDT
Is it a BigBang you hear??
Link Posted: 2/21/2006 11:01:20 AM EDT

Originally Posted By BigBang:
Is it a BigBang you hear??



Aren't you just a theory?
Link Posted: 2/21/2006 11:02:32 AM EDT

So if the gun is behind you should be able to hear the sonic boom as the bullet passes by. Then you'll hear the bang from the gun powder a short time later. Have someone shoot at you and see which is louder.

Shok
Link Posted: 2/21/2006 11:06:14 AM EDT
Link Posted: 2/21/2006 11:08:28 AM EDT

Originally Posted By -brass-:
The "bang" or "boom" or "thump" signature is from the gasses and unburnt powder rapidly expanding after the bullet leaves the barrel.

Up to that point, there isn't any noise other than the 'click' of the trigger/hammer. Only thousands of psi pressure behind the bullet to push it through the rifling grooves. Once the bullet is out of the way, the unburnt powder burns in newfound air (muzzle flash and some noise), and the pressure expands in all directions (most of the noise you hear). Supressors work by lowering the temperature and slowing down the rate the pressure escapes the muzzle after the bullet leaves.

Downrange, the sound of the bullet is more like a firecracker, which is the supersonic round. A subsonic round downrange isn't really audible unless it hits an object.




veeeery interesting. thank you.
Link Posted: 2/21/2006 11:08:32 AM EDT
You don't really hear a sonic boom from a bullet, it is more like someone tearing a large beedsheet downrange. If you shoot a supersonic round past a row of telephone posts, you will hear what sound like a whip cracking as the sonic shock wave intersects each post.

During my Army days (some 19 years ago), we had one range that was called known distance downrange feedback. Half the company was squadded at any one time as the pit crew. We pulled targets for those firing and were situated downrange under the huge berm, fully protected from the direct action of the rifles but not from overhead fire. After the shooters fired, we would pull the targets down using a pulley system to mark the hits with 4" diameter circles of bright color. Anyhow, because we were right under the targets when the bullets hit, we could hear the sonic crack of the bullet hitting the targets. Sounded just like a bullwhip cracking. Mind you, the firing line was some 300 meters away and the reports from the rifles was just a fraction of the sonic crack.

If you want to do this, you don't need to sign up for military, just get a service rifle type AR15 and visit a CMP shooting club. Many clubs still use Army ranges just like the one described above.

All of what you hear from your .45 is from the rapidly expanding gases.
Link Posted: 2/21/2006 11:13:53 AM EDT

Originally Posted By Keith_J:
You don't really hear a sonic boom from a bullet, it is more like someone tearing a large beedsheet downrange. If you shoot a supersonic round past a row of telephone posts, you will hear what sound like a whip cracking as the sonic shock wave intersects each post.

During my Army days (some 19 years ago), we had one range that was called known distance downrange feedback. Half the company was squadded at any one time as the pit crew. We pulled targets for those firing and were situated downrange under the huge berm, fully protected from the direct action of the rifles but not from overhead fire. After the shooters fired, we would pull the targets down using a pulley system to mark the hits with 4" diameter circles of bright color. Anyhow, because we were right under the targets when the bullets hit, we could hear the sonic crack of the bullet hitting the targets. Sounded just like a bullwhip cracking. Mind you, the firing line was some 300 meters away and the reports from the rifles was just a fraction of the sonic crack.

If you want to do this, you don't need to sign up for military, just get a service rifle type AR15 and visit a CMP shooting club. Many clubs still use Army ranges just like the one described above.

All of what you hear from your .45 is from the rapidly expanding gases.



I pulled targets when I was in my clubs junior program. I didn't figure it would be loud down in the pits. MY ears were ringing for a week after that day. I always wore my ear plugs in the pit after that.
Link Posted: 2/21/2006 11:30:03 AM EDT
good question. tag for good info
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