How about a sabot to hold the bullet when it is in the barrel and to provide a gas seal, while the bullet has an axial through hole to allow the air to pass from the tip to the base after the bullet exits the barrel and the sabot drops off?
Just a thought!
Mark
EDIT: I remembered I had this picture uploaded already!
Last edited by markinalpine; 09-27-2013 at 01:39 PM.
Any way you sell it,
No matter how you spell it,
When you start to smell it,
BO Stinks!
Hate to be a party pooper but the US Government can't do it with airplanes.
Even the most advanced stealth airplanes have to fly sub-sonic to be quiet.
First reload: .22 Hornet. 1956.
More at: http://reloadingtips.com/
"Any man who thinks he can be happy and prosperous by letting the
government take care of him better take a closer look at the American Indian."
- Henry Ford
Yep, me too and hate to be another party pooper. No way around it. ANY KIND or SHAPE of solid object that travels super sonic through the air will generate a "sonic" compression wave with the resulting sound. Additonally, the bullet is not the only thing that produces a sonic "crack" when fired. Even if the bullet leaves the muzzle a little sub sonic, the gasses leaving the muzzle, just as the bullet leaves, may be super sonic and can also emit the "crack".Originally Posted by williamwaco
I think OP was talking about developing a bullet that would allow the maximum reduction of sound with supersonic ammo fired from a suppressor.
There is no replacement for displacement
You could us those deer whistles that you install on your bumper and are supposed to alarm the deer so much that they flee in terror. Just put the whistle in backwards and the deer would be irresistibly drawn to the shot. Presto! self guided deer bullets.
Good luck in your endeavor sir, it should be an interesting project getting a bullet into that shape to say the least.
Artful, that was probably one of the coolest videos I've ever seen, thanks for sharing that.
Sully
Thought the thread was open to all ideas. No? Successfully suppressing a large caliber rifle round will require at least a large coffee can or larger size suppresser. Forget the finned bullet- the engineering of that will take all the skill and knowledge few have plus a lot of blown up parts during the "testing" process.
So to the finned contraption bullet. How in the world would putting fins on the nose of a bullet reduce sonic crack- no matter if the fins are pitched to push or pull through the air based on twist rate of the bore??? The exposed nose of the bullet will generate a compression wave PLUS each leading edge of each fin will have it's own compression wave. Even if a finned or hollow or corkscrew or cubic or sprinkled with fairy dust or whatever supersonic bullet in combination with some suppresser reduced sonic crack, I bet it would be a tack driverSorry I entered this thread.
Last edited by fouronesix; 09-27-2013 at 06:19 PM.
NOT that large really - 7.62x54R M38 Mosin Scout with AAC Cyclone .308 can.
click pic to enlarge
Last edited by Artful; 09-27-2013 at 06:46 PM.
je suis charlie
It is better to live one day as a LION than a dozen days as a Sheep.
Thomas Jefferson Quotations:
"The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government."
Now, that is thinking outside the box.You could us those deer whistles that you install on your bumper and are supposed to alarm the deer so much that they flee in terror. Just put the whistle in backwards and the deer would be irresistibly drawn to the shot. Presto! self guided deer bullets.
No, my 458 socom suppressor is only 2" in diameter and it makes less noise than my factory (AAC) cans.Successfully suppressing a large caliber rifle round will require at least a large coffee can or larger size suppresser.
It does have a lot of volume but to keep it short(er) it telescopes back over the barrel.
Have your guys seen this test chart with 308 caliber bullets?
Notice they tried two different conventional bullet shapes to see if it made a difference in sound signiture - it didn't at supersonic speeds.
Smaller projectiles at supersonic speeds make smaller sonic booms
larger projectiles at supersonic speeds make larger sonic booms....
Using same suppressor with 7.62x51, 7.62x54R and 243 - the 243 is quieter even though the baffles in the can are less efficient because the 243 bullet makes a smaller sonic boom.
je suis charlie
It is better to live one day as a LION than a dozen days as a Sheep.
Thomas Jefferson Quotations:
"The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government."
Nice .458 SOCOM project is the can a Form 1 then?
je suis charlie
It is better to live one day as a LION than a dozen days as a Sheep.
Thomas Jefferson Quotations:
"The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government."
Sorry I wasn't trying to upset anyone, I'm just saying that if the gasses are supersonic or not doesn't matter much in the OP's case because the suppressor takes care of that.Thought the thread was open to all ideas. No? Successfully suppressing a large caliber rifle round will require at least a large coffee can or larger size suppresser. Forget the finned bullet- the engineering of that will take all the skill and knowledge few have plus a lot of blown up parts during the "testing" process.
So to the finned contraption bullet. How in the world would putting fins on the nose of a bullet reduce sonic crack- no matter if the fins are pitched to push or pull through the air based on twist rate of the bore??? The exposed nose of the bullet will generate a compression wave PLUS each leading edge of each fin will have it's own compression wave. Even if a finned or hollow or corkscrew or cubic or sprinkled with fairy dust or whatever supersonic bullet in combination with some suppresser reduced sonic crack, I bet it would be a tack driver
I'm not sure but I think that you're not taking into account the ultra-high RPM's that the rifling will impart on the bullet and the "Impeller" action that the fins will produce. This is why it will be critical to find the correct pitch for the "Impeller-Fins."
Try calculating the RPMs on your fastest moving cast lead projectile fired from a standard 1 in 10 twist 30 caliber barrel with the bullet moving at about 1800 fps. Then do the calculation using a 168 grain bullet traveling at about 2700 fps out of the same 1 in 10 twist barrel. Those fins are rotating far faster than the bullet is moving forward.
I think if the fins are correctly calibrated, the suction that they'll induce at the front of the bullet; even one traveling at 2700 fps, will be enough to lessen or eliminate the pressure wave that stacks up ahead of the bullet and eventually slips back and collapses at the base of the bullet.
This is just how I picture it in my mind. Right now there's no telling if it will really work. I'll just have to try it first.
HollowPoint
Wow sweet setup on the458. By looking at the underwater shoots you could figure to get MAXIMUM effect you would need a massive unwieldy suppressor. It's always a balance of size & weight to make it quiet. If the 458 muffler was 8" round & a foot longer it may be almost silent but who would carry it. Maybe add wheels & a kickstand.
They said it couldn't be done
So he smiled and set right to it
And after many weeks of ardious work
He found he couldn't do it.
Yes, the 458 can is on a form 1, there are some more photos of it here http://s121.photobucket.com/user/jmo...?sort=6&page=1
freebullet, for max effect you would be inside a room and just shoot through the wall. If you can control the exit airflow you can compress the air inside the can much more than water can control the air pressure.
On the other hand, if you fill a steel container with water and freeze it, water in that state will often split steel. So you need someone to freeze themselves and an AK in a pool solid then post the video, I bet it looks a lot different...
Bigger doesn't make quieter all the time - the baffle designs have to work the gases to exchange the energy into heat to reduce the sound signature, look up suppressed airguns and watch a view video's and you'll see even without gunpowder burning you have projectile noise.
If you had a "boom" on your boolit, like the jet in the Nasa pic - you might lessen the noise but getting the boolit to stabilize will be the trick.
je suis charlie
It is better to live one day as a LION than a dozen days as a Sheep.
Thomas Jefferson Quotations:
"The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government."
1st: Artful - GREAT video of the shots under water. I pulled my kids over to view them as a great tutorial.
2nd: HollowPoint - Do not limit yourself because you do not have a fancy piece of paper stating you have a degree. I have one of those pieces of paper. It does not do the work or you. Unfortuneatley most Engineers are quicker to tell you why your idea won't work, than to try to help your idea work. More good ideas get killed before they get started because an Engineer states it can not be done. My best bosses over the years have let me try crazy ideas in order to let me learn what works and what does not work based on experience. Degrees are nice and yes, very helpful, but you learn more from failure than from success. (As long as you don't give up!)
PS - As an engineer, I think your current drawing will not work.
I'm with ya BNE - but I'd say try a stick stuck in a hollow point and see if it has a noticeable difference.
NASA did F5E with a knife nose and it did have a measurable drop in sonic boom noise
but that's not going to work with a rotating projectile !
Northrop Grumman Unveils Concept For Quiet Supersonic Aircraft
I don't think the active isentropic air inlet and extensive laminar aerodynamics
is going to be possible in a cheap to shoot boolit either...
http://www.spacedaily.com/news/plane-sonic-02b.html
http://www.faa.gov/about/office_org/...a-Northrop.pdf
je suis charlie
It is better to live one day as a LION than a dozen days as a Sheep.
Thomas Jefferson Quotations:
"The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government."
Here is a pic of a shockwawe.
As you can see the wawe starts at the point and anything under it is "hidden", so your "impeller" is useless.
Secondly there is rotational speed.
The pitch og the impeller might be tuned to the rifling pitch but remember that a bullet fired looses actual speed much faster than rotational speed.
In other words: It might work at muzzle but after a short time the "impeller" will start to rotate faster than forward speed and cavitate big time.
Here is something to read about aerodynamics:
http://waterocket.explorer.free.fr/aerodynamics.htm
Posting Permissions
| BP | Bronze Point | IMR | Improved Military Rifle | PTD | Pointed |
| BR | Bench Rest | M | Magnum | RN | Round Nose |
| BT | Boat Tail | PL | Power-Lokt | SP | Soft Point |
| C | Compressed Charge | PR | Primer | SPCL | Soft Point "Core-Lokt" |
| HP | Hollow Point | PSPCL | Pointed Soft Point "Core Lokt" | C.O.L. | Cartridge Overall Length |
| PSP | Pointed Soft Point | Spz | Spitzer Point | SBT | Spitzer Boat Tail |
| LRN | Lead Round Nose | LWC | Lead Wad Cutter | LSWC | Lead Semi Wad Cutter |
| GC | Gas Check |
Reply With Quote
