quote:

ORIGINAL: Vendaval


"Military Tracks Speeding Bullets Back to Source"By Jeremy Hsu
Scienceline
posted: 06 March 2007
02:09 pm ET

http://www.livescience.com/technology/070306_bullet_tracking.html

"As the gun is fired and the bullet’s shockwave expands outward, a computer program records the different times at which the shockwave arrives at each microphone. Based on the difference in arrival times and other consistent factors, the computer can calculate the angle from which the bullet came. This way Maher can test different guns and bullets by firing them from different angles with respect to the microphones.
 
The process of identifying the location of a fired shot is further compounded when microphones pick up background noise in addition to the bullet shockwave and the sound of the gunshot. Heavy background noises, such as would happen if a sniper fired on a patrol in the middle of a bustling marketplace, are likely to be the case in real-life situations."

quote:

ORIGINAL: Sinergy


It is only a matter of time.  They already have radar systems which home in on the location a mortar shell is fired from.
I knew this was available for artillery but did not know it was workable for mortars because of the short flight time and high angle of trajectory.  Please hook me up with more data...I am most interested in this.
thompson
While sound is useful for triangulation purposes, a solid projectile can be picked up on radar.

Sinergy

quote:

ORIGINAL: Real0ne

yeh if its not clear most guns when fired have ammo that comes out of the barrel faster then mach 1.  mach 1 is the sound barrier which is when an object travels through air approximately 1130 feet per sec at 70degrees at sea level. (it varies with temp and density)

Anyway they like to sound impressive but alls a sniper needs to do is take your 50 cal use a 750 grain moly round go out to 2000 yards from the mark adjust the powder load so that the slug is travelling less than 1000 feet per second when it passes through the area of microphones and they wont be able to discern it from the background noise even though it came out of the barrel at supersonic speeds.

Like rfid its so easily defeatable its nearly a joke, that and radar detecting an object flying at near mach 1 the size of your finger to 1st knuckle, or a pencil, not any time soon.

quote:

ORIGINAL: Vendaval

Thank you for that information, thompson. 300 yards does sound
too close for a sniper's position.

quote:

ORIGINAL: thompsonx

quote:

ORIGINAL: Real0ne

yeh if its not clear most guns when fired have ammo that comes out of the barrel faster then mach 1.  mach 1 is the sound barrier which is when an object travels through air approximately 1130 feet per sec at 70degrees at sea level. (it varies with temp and density)

Anyway they like to sound impressive but alls a sniper needs to do is take your 50 cal use a 750 grain moly round go out to 2000 yards from the mark adjust the powder load so that the slug is travelling less than 1000 feet per second when it passes through the area of microphones and they wont be able to discern it from the background noise even though it came out of the barrel at supersonic speeds.

Like rfid its so easily defeatable its nearly a joke, that and radar detecting an object flying at near mach 1 the size of your finger to 1st knuckle, or a pencil, not any time soon.

Real0ne:
The bullet has to leave the muzzel at subsonic spead to be silenced.  Thus the lethality of a 750 gr. bullet at 2000 yards is non existant.  We had the best luck with .30 cal. 110 gr. boat tail loaded down to about 1000 fps max lethal range was about 300 yards with a silencer.
thompson

quote:

ORIGINAL: thompsonx

quote:

ORIGINAL: Sinergy


It is only a matter of time.  They already have radar systems which home in on the location a mortar shell is fired from.
I knew this was available for artillery but did not know it was workable for mortars because of the short flight time and high angle of trajectory.  Please hook me up with more data...I am most interested in this.
thompson
While sound is useful for triangulation purposes, a solid projectile can be picked up on radar.

Sinergy

quote:

ORIGINAL: Sinergy

quote:

ORIGINAL: thompsonx

quote:

ORIGINAL: Sinergy


It is only a matter of time.  They already have radar systems which home in on the location a mortar shell is fired from.
I knew this was available for artillery but did not know it was workable for mortars because of the short flight time and high angle of trajectory.  Please hook me up with more data...I am most interested in this.
thompson
While sound is useful for triangulation purposes, a solid projectile can be picked up on radar.

Sinergy

I remember reading about it in Popular Mechanics a few months ago.  I will look around for the article.

Sinergy

Editted because I found some relevant links.  http://www.madsci.org/posts/archives/jun99/930284813.Eg.r.html or
http://www.kokhavivpublications.com/2004/israel/12/0412300944.html

quote:

ORIGINAL: Real0ne

quote:

ORIGINAL: thompsonx

quote:

ORIGINAL: Real0ne

yeh if its not clear most guns when fired have ammo that comes out of the barrel faster then mach 1.  mach 1 is the sound barrier which is when an object travels through air approximately 1130 feet per sec at 70degrees at sea level. (it varies with temp and density)

Anyway they like to sound impressive but alls a sniper needs to do is take your 50 cal use a 750 grain moly round go out to 2000 yards from the mark adjust the powder load so that the slug is travelling less than 1000 feet per second when it passes through the area of microphones and they wont be able to discern it from the background noise even though it came out of the barrel at supersonic speeds.

Like rfid its so easily defeatable its nearly a joke, that and radar detecting an object flying at near mach 1 the size of your finger to 1st knuckle, or a pencil, not any time soon.

Real0ne:
The bullet has to leave the muzzel at subsonic spead to be silenced.  Thus the lethality of a 750 gr. bullet at 2000 yards is non existant.  We had the best luck with .30 cal. 110 gr. boat tail loaded down to about 1000 fps max lethal range was about 300 yards with a silencer.
thompson

well there is more to my point than meets the eye at first glance.
No there isn't
assuming the microphones are within 300 yards of the target

Yes i realize that to be completely silenced you have to go under about 1050 ft per second muzzle vel.  However the microphones are being used to pinpoint and triangulate the "exact" location of the shooter.
Therefore the speed of the bullet after it leaves the muzzel is irrelevant.

At 2000 yards the report from the bullet running super sonic is so scattered by the time the mark hears it that its difficult to determine if its in one of 4 quadrants. N, w, e south much less exactly where the shooter is due to diffraction and dispersion and nearly impossible if the mark has buildings and other obstacles nearby to reflect the sound.

There would be a super sonic report anyway.  However by making sure the round is subsonic when crossing the microphoned area there is no way to pinpoint beyond a huge general direction and that is only if there is no building clutter or trees for the sound to reflect off of in the vicinity.
The mikes do not care where the bullet is.  They are measuring the sound coming out of the muzzel which is where the shooter is.

110 grain round in a 30 is seriously shitty ballistics for a 300 yard shot in unpredictable conditions.
Check your reloading tables.  I have both Norma and RCBS and they both agree that a 110 grain .308 bullet is accurate at 300 yards...the problem is lethality.  Since it starts out at about 1000 fps and does not have much mass it looses punch pretty quickly.  This round  is not for body shots.

imagine this for a moment.  silenced 50bmg. No blast report. i would have been better said to make that 800 grains btw.
As I have previously mentioned in order to get it out of the muzzel at subsonic speed there is not enough umph to push that slug far enough to be effective.  A .50 pushing 800 grains out of the muzzel at subsonic speed is going to limit your lethal range to pretty much rock throwing distances.

At 800 grains the bullet will break the sound barrier till about roughly 500 yards to the 2000 yard target.  The round would be travelling about the same subsonic speed as a 45 acp and pack roughly 3 times the energy as the 45 acp, which roughly between 850 - 950 feet per second with about 850 ftlbs of energy if memory serves.
The .45 acp goes 802 fps but it is pushing a 200 grain bullet not 800 and it is only lethal out to about 100 yards but the balistics are too poor for accuracy past about 50 yards 

The 50 BMG runnin 800 gr at 2000 yards will dump about 2200 - 2500 ft pounds of energy on impact.  Enough to kill two men one standing behind the other even at that subsonic speed.  these are just roughed in numbers that i slapstick calculated in my head so dont sight in using them LOL  but they should be reasonably close or close enough for this conversation.
I am sure that there are no tables that would show what you are looking for in a .50 with smokless powder but look up the old hawkings .50 with black powder.  They were just over 1200 fps if I remember correctly they were pushing a much smaller slug.  a 1" group at 100 yards is something that people cheer about.

i changed to 800 grains because a standard factory round can be used with no need to modify or hand load.

The problem with the 50 isnt how lethal it is at that range the problem is getting good match ammo to do the shot in the first place and actually hit the target.
Hathcocks best shot was about 2000 yards using NM ammo from frankfort arsenal.  Not every one can shoot like Carlos.  Most good shooters can hold 1moa at 1000 yards.  Beyond that you are in the land of the gods.

i do agree that 30 cal is the best all around general purpose snipe rifle, specifically the 338, but when you need subsonic at range and you really want to reach out and touch someone bigger is better for many reasons.
All I can suggest to you is to do the math.  You are not going to push 800 grains 2000 yards when it leaves the muzzel subsonic.

example: take a 16" 1 ton round from a ship, all it has to do is fall near ya 20 miles away and you are dead.

Big holes kill things better than small holes and big caliber for really outrageous distance.

110gr boatail in a .308?  you sure about the boatail?  round nose maybe?
Again look in the book...any good reloading manual will do.

That sounds more like a 6mm round to me.  To lazy to look it up tho LOL
That is why you are wrong...stop being lazy

Now if they have those microphones 1000 yards rom the target and zero ground clutter that might get more dificult.
Again all they are looking for is the shooter not the bullet. It makes no difference where the mikes are they are listening for the report from the muzzel which is where the shooter is.
thompson

quote:

ORIGINAL: Sinergy

quote:

ORIGINAL: thompsonx

quote:

ORIGINAL: Sinergy


It is only a matter of time.  They already have radar systems which home in on the location a mortar shell is fired from.
I knew this was available for artillery but did not know it was workable for mortars because of the short flight time and high angle of trajectory.  Please hook me up with more data...I am most interested in this.
thompson
While sound is useful for triangulation purposes, a solid projectile can be picked up on radar.

Sinergy

I remember reading about it in Popular Mechanics a few months ago.  I will look around for the article.

Sinergy

Editted because I found some relevant links.  http://www.madsci.org/posts/archives/jun99/930284813.Eg.r.html or
http://www.kokhavivpublications.com/2004/israel/12/0412300944.html

quote:

ORIGINAL: thompsonx

quote:

ORIGINAL: Sinergy

quote:

ORIGINAL: thompsonx

quote:

ORIGINAL: Sinergy


It is only a matter of time.  They already have radar systems which home in on the location a mortar shell is fired from.
I knew this was available for artillery but did not know it was workable for mortars because of the short flight time and high angle of trajectory.  Please hook me up with more data...I am most interested in this.
thompson
While sound is useful for triangulation purposes, a solid projectile can be picked up on radar.

Sinergy

I remember reading about it in Popular Mechanics a few months ago.  I will look around for the article.

Sinergy

Editted because I found some relevant links.  http://www.madsci.org/posts/archives/jun99/930284813.Eg.r.html or
http://www.kokhavivpublications.com/2004/israel/12/0412300944.html

Sinergy:
Thanx for the links but while the tag line calls out motars the text limits itself to flat trajectory weaponry.  The newest data is about 3 years old and they are talking about stuff that is the size of a semi.  Not really very tactical.  If you find something on mortars specifically I would be interested in reading about it.
thompson

quote:

ORIGINAL: thompsonx

quote:

ORIGINAL: Real0ne

quote:

ORIGINAL: thompsonx

quote:

ORIGINAL: Real0ne

yeh if its not clear most guns when fired have ammo that comes out of the barrel faster then mach 1.  mach 1 is the sound barrier which is when an object travels through air approximately 1130 feet per sec at 70degrees at sea level. (it varies with temp and density)

Anyway they like to sound impressive but alls a sniper needs to do is take your 50 cal use a 750 grain moly round go out to 2000 yards from the mark adjust the powder load so that the slug is travelling less than 1000 feet per second when it passes through the area of microphones and they wont be able to discern it from the background noise even though it came out of the barrel at supersonic speeds.

Like rfid its so easily defeatable its nearly a joke, that and radar detecting an object flying at near mach 1 the size of your finger to 1st knuckle, or a pencil, not any time soon.

Real0ne:
The bullet has to leave the muzzel at subsonic spead to be silenced.  Thus the lethality of a 750 gr. bullet at 2000 yards is non existant.  We had the best luck with .30 cal. 110 gr. boat tail loaded down to about 1000 fps max lethal range was about 300 yards with a silencer.
thompson

well there is more to my point than meets the eye at first glance.
No there isn't
assuming the microphones are within 300 yards of the target

Yes i realize that to be completely silenced you have to go under about 1050 ft per second muzzle vel.  However the microphones are being used to pinpoint and triangulate the "exact" location of the shooter.
Therefore the speed of the bullet after it leaves the muzzel is irrelevant.

At 2000 yards the report from the bullet running super sonic is so scattered by the time the mark hears it that its difficult to determine if its in one of 4 quadrants. N, w, e south much less exactly where the shooter is due to diffraction and dispersion and nearly impossible if the mark has buildings and other obstacles nearby to reflect the sound.

There would be a super sonic report anyway.  However by making sure the round is subsonic when crossing the microphoned area there is no way to pinpoint beyond a huge general direction and that is only if there is no building clutter or trees for the sound to reflect off of in the vicinity.
The mikes do not care where the bullet is.  They are measuring the sound coming out of the muzzel which is where the shooter is.

110 grain round in a 30 is seriously shitty ballistics for a 300 yard shot in unpredictable conditions.
Check your reloading tables.  I have both Norma and RCBS and they both agree that a 110 grain .308 bullet is accurate at 300 yards...the problem is lethality.  Since it starts out at about 1000 fps and does not have much mass it looses punch pretty quickly.  This round  is not for body shots.

imagine this for a moment.  silenced 50bmg. No blast report. i would have been better said to make that 800 grains btw.
As I have previously mentioned in order to get it out of the muzzel at subsonic speed there is not enough umph to push that slug far enough to be effective.  A .50 pushing 800 grains out of the muzzel at subsonic speed is going to limit your lethal range to pretty much rock throwing distances.

At 800 grains the bullet will break the sound barrier till about roughly 500 yards to the 2000 yard target.  The round would be travelling about the same subsonic speed as a 45 acp and pack roughly 3 times the energy as the 45 acp, which roughly between 850 - 950 feet per second with about 850 ftlbs of energy if memory serves.
The .45 acp goes 802 fps but it is pushing a 200 grain bullet not 800 and it is only lethal out to about 100 yards but the balistics are too poor for accuracy past about 50 yards 

The 50 BMG runnin 800 gr at 2000 yards will dump about 2200 - 2500 ft pounds of energy on impact.  Enough to kill two men one standing behind the other even at that subsonic speed.  these are just roughed in numbers that i slapstick calculated in my head so dont sight in using them LOL  but they should be reasonably close or close enough for this conversation.
I am sure that there are no tables that would show what you are looking for in a .50 with smokless powder but look up the old hawkings .50 with black powder.  They were just over 1200 fps if I remember correctly they were pushing a much smaller slug.  a 1" group at 100 yards is something that people cheer about.

i changed to 800 grains because a standard factory round can be used with no need to modify or hand load.

The problem with the 50 isnt how lethal it is at that range the problem is getting good match ammo to do the shot in the first place and actually hit the target.
Hathcocks best shot was about 2000 yards using NM ammo from frankfort arsenal.  Not every one can shoot like Carlos.  Most good shooters can hold 1moa at 1000 yards.  Beyond that you are in the land of the gods.

i do agree that 30 cal is the best all around general purpose snipe rifle, specifically the 338, but when you need subsonic at range and you really want to reach out and touch someone bigger is better for many reasons.
All I can suggest to you is to do the math.  You are not going to push 800 grains 2000 yards when it leaves the muzzel subsonic.

example: take a 16" 1 ton round from a ship, all it has to do is fall near ya 20 miles away and you are dead.

Big holes kill things better than small holes and big caliber for really outrageous distance.

110gr boatail in a .308?  you sure about the boatail?  round nose maybe?
Again look in the book...any good reloading manual will do.

That sounds more like a 6mm round to me.  To lazy to look it up tho LOL
That is why you are wrong...stop being lazy

Now if they have those microphones 1000 yards rom the target and zero ground clutter that might get more dificult.
Again all they are looking for is the shooter not the bullet. It makes no difference where the mikes are they are listening for the report from the muzzel which is where the shooter is.
thompson