J
JACK CHASTAIN
Guest
If we had a hypothetical switch to turn off the sound on a gunshot -would the point of impact change?
John Kielly
Shari's fan club
Depends where you're listening from.
J
JACK CHASTAIN
Guest
Jack:
Here's a hypothetical answer.... Who cares...
Kinda like that other question.. If you fart in the woods and no one else is around, does it still smell...
Dave
Who cares is the point exactly........... Until sound is debated it could be to date -an unknown tuning factor. The most obvious factor about guns is overlooked. I read a post squeeze the trigger exactly the same every time because it influences point of impact. Even minute details are critical to accuracy.
I can't get an intellengent answer to an intellegent question. You 'toters ignore the most obvious thing the guy in the next county is aware of every time you shoot. I would just like to know does sound effect the point of impact. You guys have about 10 pat answers that could be put into FAQ (frequently asked questions) and this page could be turned off. Anyone ask question #11 and he is rediculed. Honestly i wouldn't expect anything else from this bunch 'cool-aiders.
Add a J&J slide and some swear accuracy improves. The J&J does change the sound when the gun is fired. "They say" Accuracy comes from the bullet being realesed in stable air or is it? Why is the change of sound ignored? "They say" Vibrations are critical but the biggest thing about a gunshot is sound and it is never mentioned. Is it because i'm asking questions to a bunch of polly parrots?
I
inspireart
Guest
Back in the 40's the the US Army did a test on factors effecting a .22 bullet's flight. Anybody remember those photo's depicting the shock waves effecting a bullet exiting a barrel. Sound was one of the factors depicted. Remember a bullet is operating at the edge of the trans sonic range. There is turbulence produced as an airfoil approaches critical Mach. I will ask Dr. Hachey. It is nice to have access to a Phd who is RBA Hall of Fame member. He mentioned the study in context to small-bore bloop tubes.
John Kielly
Shari's fan club
Jack,
Sorry, I thought you were making a joke.
Interesting your observations about the slide. In the centrefire sphere, Boots Obermeyer was said to be associated with a bloop tube type device some years back designed to improve accuracy, as it was told to me. In that case, the idea/concept was that containing the product of the explosion in a defined/confined tube was expected to "normalise" the expanding gases into a consistent column that would impinge on every fired projectile uniformly.
One guy I knew had one that worked after a fashion, but he had to adjust it to a precise location, so I wondered if it wasn't just another style of tuner in action.
John
Sorry, I thought you were making a joke.
Interesting your observations about the slide. In the centrefire sphere, Boots Obermeyer was said to be associated with a bloop tube type device some years back designed to improve accuracy, as it was told to me. In that case, the idea/concept was that containing the product of the explosion in a defined/confined tube was expected to "normalise" the expanding gases into a consistent column that would impinge on every fired projectile uniformly.
One guy I knew had one that worked after a fashion, but he had to adjust it to a precise location, so I wondered if it wasn't just another style of tuner in action.
John
David Valdina
Member
I would think the sound results from the rapidly expanding gases and the rapid movement of the bullet while in the air. If it was fired in a vacuum, the only "noise" would be in the gun itself, no air to get vibrated and transmit the sound. If there have been accuracy tests at high altitudes where the air is thinner and those are contrasted with the same tests in dense air, you might make some sort of guess as to accuracy in no air. For sure, you wouldn't need wind flags, but snugging up to the rifle with a breathing rig might take some getting used to.
J
JACK CHASTAIN
Guest
Thanks guys for your comments. This could be the dumbest question ever asked and i appreciate you guys going out on a limb and adding your comments. The J&J slide with it's noise change put me on this line of wondering. If there is an accuracy increase with the slide it is very small but it seems to help sometimes. I would not expect sound to help/hinder accuracy very much but i think it is something to talk about.
Maybe there ain't nothing here to talk about but i just wanted to hear some thoughts -comments on the subject. It's almost like if a slight wind can alter impact maybe sound could also???
Maybe there ain't nothing here to talk about but i just wanted to hear some thoughts -comments on the subject. It's almost like if a slight wind can alter impact maybe sound could also???
I
inspireart
Guest
Here is a picture of a .22 bullet with it's proceeding shock waves.
Discussion for this photo "Attached is a photo of a .22 caliber bullet done as a shadow graph. What you are seeing are the shock waves caused by the bullet displacing the air and causing it to condense into waves - the same type of thing that causes a sonic boom from a jet aircraft exceeding the speed of sound. This was really quite easy to do - given the right equipment and place to do it. This was done in a darkened room using a GenRad strobe that had a duration of about 1/30,000 of a second. A microphone and a trigger circuit were used to trip the strobe. The paper was merely place on an easel opposite the strobe and the gun was fired. It took several attempts as the microphone had to be moved a bit so that the timing was correct, but, the image was caused by the shadow of the bullet and the shock waves falling directly on the paper."
For our discussion I wish that a standard velocity .22 was used. Another poster on a photo blog did some quick measurements on the angles of the shock wave. This bullet is traveling about M=1.14.
Any engineers here? I just fly jets but do not design them.
Bruce
Discussion for this photo "Attached is a photo of a .22 caliber bullet done as a shadow graph. What you are seeing are the shock waves caused by the bullet displacing the air and causing it to condense into waves - the same type of thing that causes a sonic boom from a jet aircraft exceeding the speed of sound. This was really quite easy to do - given the right equipment and place to do it. This was done in a darkened room using a GenRad strobe that had a duration of about 1/30,000 of a second. A microphone and a trigger circuit were used to trip the strobe. The paper was merely place on an easel opposite the strobe and the gun was fired. It took several attempts as the microphone had to be moved a bit so that the timing was correct, but, the image was caused by the shadow of the bullet and the shock waves falling directly on the paper."
For our discussion I wish that a standard velocity .22 was used. Another poster on a photo blog did some quick measurements on the angles of the shock wave. This bullet is traveling about M=1.14.
Any engineers here? I just fly jets but do not design them.
Bruce
I
inspireart
Guest
Here is the discussion and photo of very high speed bullet.
The image at the right is a shadowgraph of 22-250 bullet at an approximate Mach number of 3. The recompression shock where the wake attains a constant width is nicely illustrated.
You can see from my first post how a Noodle, Slide or bloop tube might effect the proceeding shock wave. I also believe from the info below the first photo may be subsonic.
This link is what I eluded to earlier from the US Army. Anyone have better copy to post?
http://www.scribd.com/doc/19076172/Aerodynamic-Characteristics-of-22LR-Match-Ammunition
Sound and the sound barrier have a lot to do with a bullets flight.
The image at the right is a shadowgraph of 22-250 bullet at an approximate Mach number of 3. The recompression shock where the wake attains a constant width is nicely illustrated.
You can see from my first post how a Noodle, Slide or bloop tube might effect the proceeding shock wave. I also believe from the info below the first photo may be subsonic.
This link is what I eluded to earlier from the US Army. Anyone have better copy to post?
http://www.scribd.com/doc/19076172/Aerodynamic-Characteristics-of-22LR-Match-Ammunition
Sound and the sound barrier have a lot to do with a bullets flight.
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P
Professor
Guest
Sound change or change in barrel resonance?
My question would be if the sound change we hear is representative of a change in the barrels resonance frequency. Like a trombone, as the 'tube' gets longer, the frequency goes lower. As far as a tuner goes... as the frequency of resonance changes, the 'zero crossing points' move in relationship to the end of the barrel.
Adjusting the end of the noodle (or any length adjusted tuner) by adjusting the length, are we adjusting the resonance of the barrel where the bullet exits the barrel at the proper point (zero crossing point)?
Are we just adjusting the resonance frequency of the barrel?
I don't have an answer, only the question.
I'd like to hear what others think on this as well.
My question would be if the sound change we hear is representative of a change in the barrels resonance frequency. Like a trombone, as the 'tube' gets longer, the frequency goes lower. As far as a tuner goes... as the frequency of resonance changes, the 'zero crossing points' move in relationship to the end of the barrel.
Adjusting the end of the noodle (or any length adjusted tuner) by adjusting the length, are we adjusting the resonance of the barrel where the bullet exits the barrel at the proper point (zero crossing point)?
Are we just adjusting the resonance frequency of the barrel?
I don't have an answer, only the question.
I'd like to hear what others think on this as well.
Pete Wass
Well-known member
As I recall, all the Noodles I gave seen screwed onto tuners have a soft washer of some kind between the noodle and tuner. It would seem to me that resonance would be cut down a great deal and perhaps, be altered by how tight the Noodle was screwed into the tuner. It my thinking way out of bounds here?
P
Professor
Guest
Noodle
But, is that 'o' ring the reason that the noodles don't work very well by themselves?
Don't see any without the aid of a 'tuner'.
Interesting...
But, is that 'o' ring the reason that the noodles don't work very well by themselves?
Don't see any without the aid of a 'tuner'.
Interesting...
I
inspireart
Guest
Dave probably meant this as a joke. On another forum another poster asked other factors effecting accuracy besides tuning. I will leave tuning to Varmint Al, Bill Calffee, Earnest Martin and Hopewell. One of the external factors asked about was the sound barrier. So I assumed that Dave was building on a previous post. Wrong I guess but here is what I planned on adding to that discussion.
The Noodle and other Bloops offer enhanced accuracy. The theory is this: (note I said theory.) Bloops and Noodles offer a undisturbed column of air to let the gases escape and not disturb the bullet's initial flight. They may mitigate turbulence of exiting bullet out the muzzle. The bullet is at it's highest velocity exiting the muzzle. I have already shown a shock wave preceding a .22 projectile.
The exact speed of sound depends on the temperature of the air. At sea level with a temperature of 70 degrees, sound travels at about 1,128 feet per second. As temperatures fall, air becomes denser and sound travels slower. When a bullet approaches and first passes this velocity, airflow severely buffets it. The outer edge of this transonic zone, if we go with the 1,128 fps at 70 degrees, is between about 902 and 1,466 fps.
Glen Weeks of Winchester Ammunition says a bullet that does not reach the speed of sound is much less affected by air turbulence. "A shadow graph of a subsonic bullet in flight shows a shock wave being pushed in front of the bullet and flowing around the bullet," Weeks says. "But as a bullet transitions from subsonic to supersonic, the shadow graph shows the bullet piercing the shock wave and the shock wave actually adhering somewhat to the bullet." Weeks says the shock wave created at these transonic velocities causes all sorts of turbulence. That turbulence can destabilize a bullet and throw it somewhat off course.
Read more: http://www.gunsandammo.com/content/super-subsonics?page=1#ixzz1GFbuFxce
One the features of the Eley EPS bullet is it's ability to reduce turbulence hence have greater stability. It operates as an airfoil with a higher critical Mach Number. See effect of exceeding critical Mach in illustration above. Notice the transonic range begins much below the speed of sound.
The controlled expansion effect just after the muzzle may shape the wave in front of the bullet lessing turbulence. Muzzle blast dynamics are very interesting.
The Noodle and other Bloops offer enhanced accuracy. The theory is this: (note I said theory.) Bloops and Noodles offer a undisturbed column of air to let the gases escape and not disturb the bullet's initial flight. They may mitigate turbulence of exiting bullet out the muzzle. The bullet is at it's highest velocity exiting the muzzle. I have already shown a shock wave preceding a .22 projectile.
The exact speed of sound depends on the temperature of the air. At sea level with a temperature of 70 degrees, sound travels at about 1,128 feet per second. As temperatures fall, air becomes denser and sound travels slower. When a bullet approaches and first passes this velocity, airflow severely buffets it. The outer edge of this transonic zone, if we go with the 1,128 fps at 70 degrees, is between about 902 and 1,466 fps.
Glen Weeks of Winchester Ammunition says a bullet that does not reach the speed of sound is much less affected by air turbulence. "A shadow graph of a subsonic bullet in flight shows a shock wave being pushed in front of the bullet and flowing around the bullet," Weeks says. "But as a bullet transitions from subsonic to supersonic, the shadow graph shows the bullet piercing the shock wave and the shock wave actually adhering somewhat to the bullet." Weeks says the shock wave created at these transonic velocities causes all sorts of turbulence. That turbulence can destabilize a bullet and throw it somewhat off course.
Read more: http://www.gunsandammo.com/content/super-subsonics?page=1#ixzz1GFbuFxce
One the features of the Eley EPS bullet is it's ability to reduce turbulence hence have greater stability. It operates as an airfoil with a higher critical Mach Number. See effect of exceeding critical Mach in illustration above. Notice the transonic range begins much below the speed of sound.
The controlled expansion effect just after the muzzle may shape the wave in front of the bullet lessing turbulence. Muzzle blast dynamics are very interesting.
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I
inspireart
Guest
Continued:
Form the US ARMY "A precursor shock is formed as the bullet begins to accelerate down the barrel, causing compression waves to be formed in front of the bullet as the air column in front of it accelerates. In addition, leakage of propellant gases past the bullet can cause the air column to accelerate, The compression waves caused by acceleration of the air column coalesce to form a "precursor" shock. Depending on the speed of the bullet and the length of lime the bullet is in the barrel, a second precursor shock may form. The precursor flow emanating from the muzzle is easily visualized with shadowgraphs because the gas column contains mostly air as opposed to cloudy propellant gas.
After the bullet exits from the barrel and uncorks the propellant gas column behind it, the flow of the main propellant gases begins. The main propellant flow is similar to the precursor flow, only with pressure ratio typically one to two orders-of-magnitude higher. The precursor contributes very little to the over all blast effect of the gun. The propellant gas exits the barrel at a pressure ratio of 660. Because the pressure is so much higher than the precursor wave, the main blast wave quickly over takes the precursor blast wave."
A Pappas Noodle with Harrel Tuner
Alright I give up... PAPPAS HOW DOES THE DARN THING REALLY WORK?
Bruce
Form the US ARMY "A precursor shock is formed as the bullet begins to accelerate down the barrel, causing compression waves to be formed in front of the bullet as the air column in front of it accelerates. In addition, leakage of propellant gases past the bullet can cause the air column to accelerate, The compression waves caused by acceleration of the air column coalesce to form a "precursor" shock. Depending on the speed of the bullet and the length of lime the bullet is in the barrel, a second precursor shock may form. The precursor flow emanating from the muzzle is easily visualized with shadowgraphs because the gas column contains mostly air as opposed to cloudy propellant gas.
After the bullet exits from the barrel and uncorks the propellant gas column behind it, the flow of the main propellant gases begins. The main propellant flow is similar to the precursor flow, only with pressure ratio typically one to two orders-of-magnitude higher. The precursor contributes very little to the over all blast effect of the gun. The propellant gas exits the barrel at a pressure ratio of 660. Because the pressure is so much higher than the precursor wave, the main blast wave quickly over takes the precursor blast wave."
A Pappas Noodle with Harrel Tuner
Alright I give up... PAPPAS HOW DOES THE DARN THING REALLY WORK?
Bruce
J
JACK CHASTAIN
Guest
Bruce thanks for posting the pic and the input. For me the Pappas Noodle is taking me down the exploratory sound path.
With the remark about the different "washer thickness" you can use with the noodle, for me i wasn't think about that but it is an excellent point about changing the 'sound octaves. It just looks like the adjustable collar could also be used to tune the sound.
The #2 winner of last weeks PSL match was listed as using the Pappas Noodle. I do like the theory of the bullet being released into non turbulent air.
I don't know if sound plays any part in this tuning aid but it could possible be a #2 reason for increased accuracy is the adjust-ability of exit sound.
With the remark about the different "washer thickness" you can use with the noodle, for me i wasn't think about that but it is an excellent point about changing the 'sound octaves. It just looks like the adjustable collar could also be used to tune the sound.
The #2 winner of last weeks PSL match was listed as using the Pappas Noodle. I do like the theory of the bullet being released into non turbulent air.
I don't know if sound plays any part in this tuning aid but it could possible be a #2 reason for increased accuracy is the adjust-ability of exit sound.
I
inspireart
Guest
The aerodynamics I have high degree of confidence in. The blast dynamics I need help with. Any fluid dynamic types in the house?
Bruce
Bruce