Pat Speer Posted August 19, 2015 Share Posted August 19, 2015 ...the bullet was gaining velocity on the first half of its journey which was, of course, uphill. Robert, Question: What force was causing the bullet to gain velocity while traveling "uphill"? Tom I have no idea, Tom. In fact, I have never seen this on a ballistics calculator before, and I wonder if it is not an error in their computer. The laws of inertia state that a body in motion tends to stay in motion, but it doesn't say anything about gaining velocity; at least, not in this universe, anyways. I agree. It must be an error in the calculator. Velocity should be decreasing. Air resistance will reduce the bullet's velocity uphill or downhill, and an upward traveling bullet will have its vertical velocity component reduced by gravity. I read some material which suggested that a completely spent bullet, fired straight up and returning to Earth backwards, will fall around 300 fps, and be unlikely to kill someone, due to the relatively slow speed and wide area of impact, but that a bullet fired at an angle will fall at over 300 fps, and hit nose first, and be more problematic. As bullets falling nose first are more aerodynamic, they have a greater terminal velocity. Link to comment Share on other sites More sharing options...
Robert Prudhomme Posted August 19, 2015 Author Share Posted August 19, 2015 ...the bullet was gaining velocity on the first half of its journey which was, of course, uphill. Robert, Question: What force was causing the bullet to gain velocity while traveling "uphill"? Tom I have no idea, Tom. In fact, I have never seen this on a ballistics calculator before, and I wonder if it is not an error in their computer. The laws of inertia state that a body in motion tends to stay in motion, but it doesn't say anything about gaining velocity; at least, not in this universe, anyways. I agree. It must be an error in the calculator. Velocity should be decreasing. Air resistance will reduce the bullet's velocity uphill or downhill, and an upward traveling bullet will have its vertical velocity component reduced by gravity. I read some material which suggested that a completely spent bullet, fired straight up and returning to Earth backwards, will fall around 300 fps, and be unlikely to kill someone, due to the relatively slow speed and wide area of impact, but that a bullet fired at an angle will fall at over 300 fps, and hit nose first, and be more problematic. As bullets falling nose first are more aerodynamic, they have a greater terminal velocity. And your point is........ Link to comment Share on other sites More sharing options...
Tom Neal Posted August 19, 2015 Share Posted August 19, 2015 I believe I have already done this, Tom, if you go back a few posts. I calculated for the 162 grain bullet travelling at 2200 fps and for a rifle sighted in at 100 yards. Robert, I definitely did go through your earlier post. What is preventing me from being certain as to what the results mean, is their definition of "Muzzle Elevation" (Muz Elv = Horizontal inclination of gun in degrees) and what the program is doing with that information. A different calculator refers to this as the "shooting angle" and defines this as "the angle of the firearms bore to the line that is tangent to the Earth's surface." In this case, I believe that aligning the "bore" to the horizontal, and aligning the "gun" to the horizontal have the same meaning. Using a rifle that has been sighted in at 100 yards, if I put the sights on a target that has a range of 100 yards, the bullet will hit that target. According to the calculator this will occur with a Muz Elv of zero degrees. By their definition the gun barrel will be parallel to the ground. If so, the trajectory will never rise above a line through the barrel extending to the target, no compensation for bullet drop will be produced, and the shot will impact below the target. Unless I'm missing something important here, the "Muzzle Elevation" parameter in this Calculator is not setting the elevation of the gun barrel relative to horizontal, but instead is calling the elevation of the barrel required to put the sights on the target a Muzzle Elevation of zero. Tom Link to comment Share on other sites More sharing options...
Robert Prudhomme Posted August 19, 2015 Author Share Posted August 19, 2015 I have never used the Muzzle Elevation portion of that program, simply because knowing the muzzle elevation of a rifle has never been important to me. I believe you actually have to enter a value here. It is assumed that the muzzle will be elevated if you are sighting a rifle in at 100 yards; a tiny amount for 2200 fps and quite a bit more for 300 fps. Link to comment Share on other sites More sharing options...
Tom Neal Posted August 19, 2015 Share Posted August 19, 2015 I have never used the Muzzle Elevation portion of that program, simply because knowing the muzzle elevation of a rifle has never been important to me. I believe you actually have to enter a value here. In an effort to understand what the calculator is doing with the muzzle elev parameter; using a muzzle velocity of 300 fps to make the results of elevation changes more significant, I've tried incrementally raising the "muzzle elevation" parameter. As the elevation increases the impact occurs higher and higher above the target as I expected it would. Because the target is hit with the muzzle elev parameter set at zero, the gun must actually be elevated above horizontal, but there's no way to determine what elevation the calculator is actually using. Although the elevation angle for a 2200 fps bullet at a range of 100 yards is very small, what I was hoping to do was set the muzzle elevation to hit the target at a specific range, then alter only the muzzle velocity until a -10.5" error is produced. This would provide the most accurate results, but the program doesn't appear to allow this. I'm going to email the website and hopefully contact the author. Since the calculator is determining the muzzle elevation required to hit the target, it should be a simple matter to display this number. Robert, the calculations you have done are certainly accurate enough to prove that the "shallow back wound" was not created by an undercharged shot aimed at JFK's head. What I would like to do is to find or create a program that will utilize an adjustable muzzle elevation parameter and more importantly, a height differential parameter. This would allow the inclusion of the height of the "sniper's nest" into the results. Following a depressed trajectory from the 6th floor, the bullet will have a shorter time of flight, and without elevation compensation will impact above the target. I doubt LHO would be aware of this factor and would not realize he would have to aim lower to hit his target. So, if LHO was the shooter, why didn't the "back shot" pass above JFK's head, rather than hit him in the back? This could be evidence that a professional shooter overcompensated for the downhill shot, and aimed too low. It would be interesting to know how much elevation compensation would be required for a shot from the 6th floor. Tom Link to comment Share on other sites More sharing options...
Kenneth Drew Posted August 19, 2015 Share Posted August 19, 2015 Ollie Look at these photos. Do you see a problem here? Western Cartridge Co. 6.5mm Carcano cartridge .30-06 cartridge on left I don't, if the conversation is whether the bullet from the carcano would fit into the 30 06 it appears it will. Link to comment Share on other sites More sharing options...
Robert Prudhomme Posted August 19, 2015 Author Share Posted August 19, 2015 Ollie Look at these photos. Do you see a problem here? Western Cartridge Co. 6.5mm Carcano cartridge .30-06 cartridge on left I don't, if the conversation is whether the bullet from the carcano would fit into the 30 06 it appears it will. Kenneth, do you know what a sabot is? Link to comment Share on other sites More sharing options...
Robert Prudhomme Posted August 19, 2015 Author Share Posted August 19, 2015 I have never used the Muzzle Elevation portion of that program, simply because knowing the muzzle elevation of a rifle has never been important to me. I believe you actually have to enter a value here. In an effort to understand what the calculator is doing with the muzzle elev parameter; using a muzzle velocity of 300 fps to make the results of elevation changes more significant, I've tried incrementally raising the "muzzle elevation" parameter. As the elevation increases the impact occurs higher and higher above the target as I expected it would. Because the target is hit with the muzzle elev parameter set at zero, the gun must actually be elevated above horizontal, but there's no way to determine what elevation the calculator is actually using. Although the elevation angle for a 2200 fps bullet at a range of 100 yards is very small, what I was hoping to do was set the muzzle elevation to hit the target at a specific range, then alter only the muzzle velocity until a -10.5" error is produced. This would provide the most accurate results, but the program doesn't appear to allow this. I'm going to email the website and hopefully contact the author. Since the calculator is determining the muzzle elevation required to hit the target, it should be a simple matter to display this number. Robert, the calculations you have done are certainly accurate enough to prove that the "shallow back wound" was not created by an undercharged shot aimed at JFK's head. What I would like to do is to find or create a program that will utilize an adjustable muzzle elevation parameter and more importantly, a height differential parameter. This would allow the inclusion of the height of the "sniper's nest" into the results. Following a depressed trajectory from the 6th floor, the bullet will have a shorter time of flight, and without elevation compensation will impact above the target. I doubt LHO would be aware of this factor and would not realize he would have to aim lower to hit his target. So, if LHO was the shooter, why didn't the "back shot" pass above JFK's head, rather than hit him in the back? This could be evidence that a professional shooter overcompensated for the downhill shot, and aimed too low. It would be interesting to know how much elevation compensation would be required for a shot from the 6th floor. Tom Not as much as you might think. When shooting uphill OR downhill, the bullet will always go slightly higher than the point of aim. At 50 yards, this amount is a mere inch or so depending, of course, on the amount the shot is off of level. Link to comment Share on other sites More sharing options...
Kenneth Drew Posted August 19, 2015 Share Posted August 19, 2015 (edited) Ollie Look at these photos. Do you see a problem here? Western Cartridge Co. 6.5mm Carcano cartridge .30-06 cartridge on left I don't, if the conversation is whether the bullet from the carcano would fit into the 30 06 it appears it will. Kenneth, do you know what a sabot is? Yes I know that there was a theory that the 399 bullet was put into a larger cartridge and fired from the County records building. Since the 30 06 was 'crimped' around the bullet end, that is what created the theory. I don't recall any discussion in that theory as to 'velocity' of bullet,, but if it actually happened, they obviously didn't want any damage to the bullet so that it could remain 'pristine'. And I'm assuming that you know what a sabot is in my statement. Edited August 19, 2015 by Kenneth Drew Link to comment Share on other sites More sharing options...
Robert Prudhomme Posted August 20, 2015 Author Share Posted August 20, 2015 (edited) What on earth does "crimping around the bullet end" have to do with a sabot? Edited August 20, 2015 by Robert Prudhomme Link to comment Share on other sites More sharing options...
Kenneth Drew Posted August 20, 2015 Share Posted August 20, 2015 What on earth does "crimping around the bullet end" have to do with a sabot? Sorry Robert, I just assumed you knew what a sabot was. Link to comment Share on other sites More sharing options...
Robert Prudhomme Posted August 20, 2015 Author Share Posted August 20, 2015 I know exactly what a sabot is, and I have used them, as well. I don't think you or a lot of other people on this forum that think you can sabot a 6.5mm Carcano bullet into a 30-06 cartridge quite understand the concept, though. Link to comment Share on other sites More sharing options...
Kenneth Drew Posted August 20, 2015 Share Posted August 20, 2015 I know exactly what a sabot is, and I have used them, as well. I don't think you or a lot of other people on this forum that think you can sabot a 6.5mm Carcano bullet into a 30-06 cartridge quite understand the concept, though. Good, then you are familiar with this: Note, this is from Wim Dankbaar Members 1,481 posts Posted 26 November 2004 - 04:44 AM william galmor wrote: > > I read somewhere that in the early 1970's a spent rifle cartridge was > found on roof of building across the street from the book depository. Was > this ever investigated? The cartridge was a .30-30 hull found by an air-conditioning repair man ( as I recall) on the top of the COunty Records Building at the base of the rampart overlooking Dealy Plaza. The cartridge was supposedly crimped in a way that suggested a sabot round had been used in it. The seat of the cartridge was stamped, as I recall "Twin Cities Arsenal, 1954" The Twin Cities Arsenal is located in Eden Prairie, Minnesota. I talked with three engineers from the arsenal back in 1992 about the munitions they loaded there. All three, in separate interviews, said that a sabot round for that cartridge required special equipment that was ONLY available at USArmy munitions plants; that sabots could not be hand loaded into that type of cartridge until the early seventies when the equipment first became available; that none of them were ever aware of special rounds being loaded at the TCA, though it was possible. I asked if it would necessarily require records and each said that ALL operations at the Arsenal required records-- but getting to them was very difficult since the plant was then being decommissioned. In seven years the plant still is not fully decommissioned. I talked to a USA Major there last year who said he knew the plant's history pretty well and he didn't believe a special load would have been done there. He said the only place it could have been made was in a special division of the arsenal at St. Louis Missouri, which was known for engineering special rounds and weapons. He was the only person of the four who asked why I wanted to know about such rounds. When I told him it involved the JFK assassination He refused to talk to me anymore. Go figure.... The question a sabot round being fired at the motorcade has been around for a long time. from what I recall, the wound to Connally's back produced a "probability cone" which included the DRB. Anyone? Claims by the ammo "experts " out there that such a round could not maintain the needed stability and accuracy for a shot from the DRB seem true enough. However, in talking to a USR sniper and an ex Green Beret "hunter", both men said not only were such rounds possible, they had used them. Craig Roberts, you out there? I was told Mary Ferrell and Jim Marrs are the experts on the history of the cartridge. Gary probably knows a lot about it, too. What part of it do you disagree with Robert? You did see that part about: 'crimped in such a way'? Seems as if sabot technology might not have been as advanced back in 63 as it is today. Link to comment Share on other sites More sharing options...
Robert Prudhomme Posted August 20, 2015 Author Share Posted August 20, 2015 Okay, Kenneth, show me how a cartridge would be "crimped in such a way" that would indicate it had been loaded with a sabot. Link to comment Share on other sites More sharing options...
Kenneth Drew Posted August 20, 2015 Share Posted August 20, 2015 Okay, Kenneth, show me how a cartridge would be "crimped in such a way" that would indicate it had been loaded with a sabot. The cartridge was a .30-30 hull found by an air-conditioning repair man ( as I recall) on the top of the COunty Records Building at the base of the rampart overlooking Dealy Plaza. The cartridge was supposedly crimped in a way that suggested a sabot round had been used in it. The seat of the cartridge was stamped, as I recall "Twin Cities Arsenal, 1954" See the sentence in bold in that paragraph. Seems as if a bullet is in a cartridge shell that it has to be sealed. Seems as if there is more than one way to accomplish that. One to use the plastic insert, the other to crimp the shell around the bullet. I suppose it depends on the difference in diameter. Link to comment Share on other sites More sharing options...
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