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#111
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casette shifting, again
On 12/17/2018 8:58 PM, Jeff Liebermann wrote:
On Tue, 18 Dec 2018 09:11:06 +0700, John B. Slocomb wrote: I'm not a ballistition (is that a word?) Nope. That's someone who operates a ballista: https://www.google.com/search?q=ballista&tbm=isch Perhaps ballisticist? but from what little I've read none of the multitude of formulas actually provides accurate results in all cases. See https://en.wikipedia.org/wiki/External_ballistics for probably more then you want to know :-) I agree, if what I was looking for is a mathemagical way to calculate the point of impact. That's quite difficult to do, considering the accumulated tolerances of all the numerous factors involved (powder load, temperature, humidity, altitude, wind, bullet weight, bullet type, barrel friction, etc). Even an over-simplified tolerance estimate of just the target width over the range is rather small. For example, a 1ft frying pan at 300 yards is: 1ft / 900ft = 0.1% accuracy Throw in all the other factors, and the % accuracy becomes much smaller. However, I'm not looking for the point of impact. I'm looking for the muzzle velocity (given the terminal velocity at some known range). I would guess(tm) that this could be calculated within to a reasonable accuracy, such as +/-10%, without much difficulty. There are myriad resources on this complex topic. Some useful or at least interesting numbers he http://wredlich.com/ny/2013/01/proje...topping-power/ -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
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#112
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casette shifting, again
On 18/12/18 7:21 pm, John B. Slocomb wrote:
On Tue, 18 Dec 2018 16:14:27 +1100, James wrote: My .222 Remington has a stainless barrel that was re-bored from .17, and the action is bedded in fibreglass and the barrel floated. A Remington Model 700. The Remington 700 was probably one of the best actions ever made. But re-bored? Wouldn't it have been cheaper to just rebarrel? I bought the rifle from a friend. He wore out the original barrel, then had the stainless .17 barrel fitted, wore that out and had it re-bored to .222 before I bought it. You would have to ask him for the reasoning. -- JS |
#113
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casette shifting, again
On Wed, 19 Dec 2018 08:01:50 +1100, James
wrote: On 18/12/18 7:21 pm, John B. Slocomb wrote: On Tue, 18 Dec 2018 16:14:27 +1100, James wrote: My .222 Remington has a stainless barrel that was re-bored from .17, and the action is bedded in fibreglass and the barrel floated. A Remington Model 700. The Remington 700 was probably one of the best actions ever made. But re-bored? Wouldn't it have been cheaper to just rebarrel? I bought the rifle from a friend. He wore out the original barrel, then had the stainless .17 barrel fitted, wore that out and had it re-bored to .222 before I bought it. You would have to ask him for the reasoning. My thought that it might be cheaper is probably because I re-barreled many actions but had no facilities to re-bore and rifle an old barrel :-) cheers, John B. |
#114
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casette shifting, again
On Tue, 18 Dec 2018 08:56:47 -0600, AMuzi wrote:
On 12/17/2018 8:58 PM, Jeff Liebermann wrote: On Tue, 18 Dec 2018 09:11:06 +0700, John B. Slocomb wrote: I'm not a ballistition (is that a word?) Nope. That's someone who operates a ballista: https://www.google.com/search?q=ballista&tbm=isch Perhaps ballisticist? but from what little I've read none of the multitude of formulas actually provides accurate results in all cases. See https://en.wikipedia.org/wiki/External_ballistics for probably more then you want to know :-) I agree, if what I was looking for is a mathemagical way to calculate the point of impact. That's quite difficult to do, considering the accumulated tolerances of all the numerous factors involved (powder load, temperature, humidity, altitude, wind, bullet weight, bullet type, barrel friction, etc). Even an over-simplified tolerance estimate of just the target width over the range is rather small. For example, a 1ft frying pan at 300 yards is: 1ft / 900ft = 0.1% accuracy Throw in all the other factors, and the % accuracy becomes much smaller. However, I'm not looking for the point of impact. I'm looking for the muzzle velocity (given the terminal velocity at some known range). I would guess(tm) that this could be calculated within to a reasonable accuracy, such as +/-10%, without much difficulty. There are myriad resources on this complex topic. Some useful or at least interesting numbers he http://wredlich.com/ny/2013/01/proje...topping-power/ A complex subject as target damage (to coin a term) depends on several factors. For example, at short range a M-16 (.22 cal) M.V. in the 3,000 f/s range creates a substantially less significant wound than a ..58 cal rifled musket with its ~1,000 f/s M.V. cheers, John B. |
#115
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casette shifting, again
On 12/17/2018 6:16 PM, John B. Slocomb wrote:
On Mon, 17 Dec 2018 15:41:14 -0800, "Mark J." wrote: On 12/15/2018 9:58 PM, John B. Slocomb wrote: On Sat, 15 Dec 2018 21:39:19 -0800 (PST), Sir Ridesalot wrote: On Saturday, December 15, 2018 at 10:43:29 PM UTC-5, John B. Slocomb wrote: On Sat, 15 Dec 2018 16:20:42 -0800 (PST), jbeattie wrote: On Saturday, December 15, 2018 at 1:59:24 PM UTC-8, AMuzi wrote: On 12/15/2018 3:04 PM, Emanuel Berg wrote: Frank Krygowski wrote: Emanuel, with all due respect, you should spend the winter reading a physics book or two. Or three. Skip the parts on electricity, atomic physics, etc. Concentrate on forces, motion, work, energy etc. - the parts that apply to bicycles. [...] Blah blah blah, you have told me this at least a dozen times by now. Probably because it is easier to be didactic/demeaning than to actually answer the questions. more. I left school without having slept through even one physics class. My reference work here is a 1955 high school textbook for $1 (9 Kr). I don't know all of even that, but I understand the world well enough to know that this headline last week: https://www.dailymail.co.uk/sciencet...soon-2022.html was completely ridiculous. The chamber pressures are in the same range, but not power, not even within a magnitude*! Power is work over time. Without some grasp of the actual world, you would not have laughed aloud when reading the headline, etc. *A typical 120mm tank round is 7.5 kilos of depleted uranium moving at 1700 m/s. The new 6.8 rifle typically moves 7.5 grams at 850 m/s. That's why you need basic physics. BTW, here's an interesting case that crossed my desk: https://www.bendbulletin.com/localst...killed-in-tank https://www.oregonlive.com/pacific-n...explosion.html Interesting object lesson for re-loaders. I'm representing a party on a collateral insurance issue. I've represented a couple big gun makers in over-pressure cases. Reloads. Too much powder or the wrong powder can blow-up guns large and small. -- Jay Beattie. One of the things I notices in the reference was that the gun had been "de-militarized" and that "was restored by Preston to working order". The term "de-militarized", at least as used by the U.S.A.F., means that the weapon is modified to a point that it cannot be fired, and cannot be repaired. In small arms usually by cutting the receiver and barrel into at least two parts, usually with a cutting torch. cheers, John B. I read the Preston put in 8oz. more powder than was the recommended load and was told that if he fired that cartridge it'd blow up the gun. Preston was also persuaded to take out more insurance due to that overloaded cartridge. Yes, I read that part too. I used to hand load for varmint rifles and of course we were always trying for that little extra speed, but we were also careful to inspect cartridge cases for signs of over pressure. I simply can't imagine anyone just shoveling in 8 ounces of extra powder. Particularly after someone "in the business" told not to. That extra 8 ounces blew my mind also. When I was maybe 30, I was helping my dad, a long-time pistol round reloader, mostly out of [my] curiosity. There was another seasoned reloader there also. I measured one shell's worth of powder and was surprised how excited they both got, exhorting me to avoid compressing or tamping down the powder ?while scooping? (details and wording are foggy years later). I was warned that any hint of ?compression? in the powder could result in a overload that could destroy a pistol. Who'd think you'd need to be careful working with explosives? Mark J. True. Gun powders are manufactured as grains and any packing or tamping down would allow more grains in the same space (measure). More explosive in the same place equals higher pressures. People that are loading right up to the maximum will weigh the powder rather then use a mechanical measure. You know, now that you mention it, I /know/ Dad used a powder scale to weigh his charges - maybe the concern was that he weighed once to determine the needed volume, then used volume after that. But memory is really foggy here; maybe we were weighing each charge. My impression at the time (which could well have been completely wrong) was that they were concerned about packing/compressing even the correct weight of powder, as if the compression was a separate concern above and beyond getting the correct weight. It was clear at the time that I wasn't understanding what the issues were (they were overseeing me like hawks, so I wasn't too worried about a serious error slipping by.) Dad did a lot of crazy things, but he was very serious about gun safety, in all its forms. Mark J. |
#116
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casette shifting, again
On Mon, 17 Dec 2018 16:37:12 -0800, sltom992 wrote:
On Sunday, December 16, 2018 at 11:04:43 AM UTC-8, Ralph Barone wrote: If I owned a major corporation with a billing system consisting of a half- million lines of COBOL and needed to add an "e-mail address" field to my printed invoices, you can bet your ass I'd be looking for a retired COBOL programmer instead of rewriting the system from scratch in the language du jour. I don't disagree with your choice. I wrote in most languages up to Python and C++. But companies don't want to fix things - they want all knew "maintainable" code. It's pretty ridiculous. Err, isn't that sentence an oxymoron; it only needs to be "maintainable" if they intent to fix it. |
#117
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casette shifting, again
On Tue, 18 Dec 2018 18:46:19 -0800, "Mark J."
wrote: On 12/17/2018 6:16 PM, John B. Slocomb wrote: On Mon, 17 Dec 2018 15:41:14 -0800, "Mark J." wrote: On 12/15/2018 9:58 PM, John B. Slocomb wrote: On Sat, 15 Dec 2018 21:39:19 -0800 (PST), Sir Ridesalot wrote: On Saturday, December 15, 2018 at 10:43:29 PM UTC-5, John B. Slocomb wrote: On Sat, 15 Dec 2018 16:20:42 -0800 (PST), jbeattie wrote: On Saturday, December 15, 2018 at 1:59:24 PM UTC-8, AMuzi wrote: On 12/15/2018 3:04 PM, Emanuel Berg wrote: Frank Krygowski wrote: Emanuel, with all due respect, you should spend the winter reading a physics book or two. Or three. Skip the parts on electricity, atomic physics, etc. Concentrate on forces, motion, work, energy etc. - the parts that apply to bicycles. [...] Blah blah blah, you have told me this at least a dozen times by now. Probably because it is easier to be didactic/demeaning than to actually answer the questions. more. I left school without having slept through even one physics class. My reference work here is a 1955 high school textbook for $1 (9 Kr). I don't know all of even that, but I understand the world well enough to know that this headline last week: https://www.dailymail.co.uk/sciencet...soon-2022.html was completely ridiculous. The chamber pressures are in the same range, but not power, not even within a magnitude*! Power is work over time. Without some grasp of the actual world, you would not have laughed aloud when reading the headline, etc. *A typical 120mm tank round is 7.5 kilos of depleted uranium moving at 1700 m/s. The new 6.8 rifle typically moves 7.5 grams at 850 m/s. That's why you need basic physics. BTW, here's an interesting case that crossed my desk: https://www.bendbulletin.com/localst...killed-in-tank https://www.oregonlive.com/pacific-n...explosion.html Interesting object lesson for re-loaders. I'm representing a party on a collateral insurance issue. I've represented a couple big gun makers in over-pressure cases. Reloads. Too much powder or the wrong powder can blow-up guns large and small. -- Jay Beattie. One of the things I notices in the reference was that the gun had been "de-militarized" and that "was restored by Preston to working order". The term "de-militarized", at least as used by the U.S.A.F., means that the weapon is modified to a point that it cannot be fired, and cannot be repaired. In small arms usually by cutting the receiver and barrel into at least two parts, usually with a cutting torch. cheers, John B. I read the Preston put in 8oz. more powder than was the recommended load and was told that if he fired that cartridge it'd blow up the gun. Preston was also persuaded to take out more insurance due to that overloaded cartridge. Yes, I read that part too. I used to hand load for varmint rifles and of course we were always trying for that little extra speed, but we were also careful to inspect cartridge cases for signs of over pressure. I simply can't imagine anyone just shoveling in 8 ounces of extra powder. Particularly after someone "in the business" told not to. That extra 8 ounces blew my mind also. When I was maybe 30, I was helping my dad, a long-time pistol round reloader, mostly out of [my] curiosity. There was another seasoned reloader there also. I measured one shell's worth of powder and was surprised how excited they both got, exhorting me to avoid compressing or tamping down the powder ?while scooping? (details and wording are foggy years later). I was warned that any hint of ?compression? in the powder could result in a overload that could destroy a pistol. Who'd think you'd need to be careful working with explosives? Mark J. True. Gun powders are manufactured as grains and any packing or tamping down would allow more grains in the same space (measure). More explosive in the same place equals higher pressures. People that are loading right up to the maximum will weigh the powder rather then use a mechanical measure. You know, now that you mention it, I /know/ Dad used a powder scale to weigh his charges - maybe the concern was that he weighed once to determine the needed volume, then used volume after that. But memory is really foggy here; maybe we were weighing each charge. My impression at the time (which could well have been completely wrong) was that they were concerned about packing/compressing even the correct weight of powder, as if the compression was a separate concern above and beyond getting the correct weight. It was clear at the time that I wasn't understanding what the issues were (they were overseeing me like hawks, so I wasn't too worried about a serious error slipping by.) Dad did a lot of crazy things, but he was very serious about gun safety, in all its forms. Mark J. Generally smokeless powder loads are measured by weight, especially when they approach maximum loads. Black powder on the other hand can be measured, and usually is, by volume. Having said that it was fairly common especially when loading lower powered cartridges in volume to use a mechanical powder measure. The progressive turret pistol cartridge loading machines work that way. Loading a cartridge with so much powder that seating the bullet compresses the powder results in higher then normal pressures when fired. As for firearm safety... shooting yourself in the foot is, they say, embarrassing and shooting someone else is likely to be a crime :-) cheers, John B. |
#118
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casette shifting, again
On Monday, December 17, 2018 at 6:16:15 PM UTC-8, John B. Slocomb wrote:
On Mon, 17 Dec 2018 15:41:14 -0800, "Mark J." wrote: On 12/15/2018 9:58 PM, John B. Slocomb wrote: On Sat, 15 Dec 2018 21:39:19 -0800 (PST), Sir Ridesalot wrote: On Saturday, December 15, 2018 at 10:43:29 PM UTC-5, John B. Slocomb wrote: On Sat, 15 Dec 2018 16:20:42 -0800 (PST), jbeattie wrote: On Saturday, December 15, 2018 at 1:59:24 PM UTC-8, AMuzi wrote: On 12/15/2018 3:04 PM, Emanuel Berg wrote: Frank Krygowski wrote: Emanuel, with all due respect, you should spend the winter reading a physics book or two. Or three. Skip the parts on electricity, atomic physics, etc. Concentrate on forces, motion, work, energy etc. - the parts that apply to bicycles. [...] Blah blah blah, you have told me this at least a dozen times by now. Probably because it is easier to be didactic/demeaning than to actually answer the questions. more. I left school without having slept through even one physics class. My reference work here is a 1955 high school textbook for $1 (9 Kr). I don't know all of even that, but I understand the world well enough to know that this headline last week: https://www.dailymail.co.uk/sciencet...soon-2022.html was completely ridiculous. The chamber pressures are in the same range, but not power, not even within a magnitude*! Power is work over time. Without some grasp of the actual world, you would not have laughed aloud when reading the headline, etc. *A typical 120mm tank round is 7.5 kilos of depleted uranium moving at 1700 m/s. The new 6.8 rifle typically moves 7.5 grams at 850 m/s. That's why you need basic physics. BTW, here's an interesting case that crossed my desk: https://www.bendbulletin.com/localst...killed-in-tank https://www.oregonlive.com/pacific-n...explosion.html Interesting object lesson for re-loaders. I'm representing a party on a collateral insurance issue. I've represented a couple big gun makers in over-pressure cases. Reloads. Too much powder or the wrong powder can blow-up guns large and small. -- Jay Beattie. One of the things I notices in the reference was that the gun had been "de-militarized" and that "was restored by Preston to working order".. The term "de-militarized", at least as used by the U.S.A.F., means that the weapon is modified to a point that it cannot be fired, and cannot be repaired. In small arms usually by cutting the receiver and barrel into at least two parts, usually with a cutting torch. cheers, John B. I read the Preston put in 8oz. more powder than was the recommended load and was told that if he fired that cartridge it'd blow up the gun. Preston was also persuaded to take out more insurance due to that overloaded cartridge. Yes, I read that part too. I used to hand load for varmint rifles and of course we were always trying for that little extra speed, but we were also careful to inspect cartridge cases for signs of over pressure. I simply can't imagine anyone just shoveling in 8 ounces of extra powder. Particularly after someone "in the business" told not to. That extra 8 ounces blew my mind also. When I was maybe 30, I was helping my dad, a long-time pistol round reloader, mostly out of [my] curiosity. There was another seasoned reloader there also. I measured one shell's worth of powder and was surprised how excited they both got, exhorting me to avoid compressing or tamping down the powder ?while scooping? (details and wording are foggy years later). I was warned that any hint of ?compression? in the powder could result in a overload that could destroy a pistol. Who'd think you'd need to be careful working with explosives? Mark J. True. Gun powders are manufactured as grains and any packing or tamping down would allow more grains in the same space (measure). More explosive in the same place equals higher pressures. People that are loading right up to the maximum will weigh the powder rather then use a mechanical measure. cheers, John B. John - it wasn't until around WW I that bullets became supersonic. For most of the time of firearms, the loads and powder wouldn't allow that. You would hear the shot before the bullet struck. You could see an animal jump before the bullet struck. And muzzle loaders or anything using round balls could not fire supersonic. You usually do not use more powder and especially tamping it down because that is asking for a chamber explosion. You use a hotter or cooler burning powder. A chamber explosion would usually burn your hands but the worse case is exploding the section holding the round - the cylinder in a revolver or the entire rear section of an automatic or even worse blowing the entire slide off into your face. These sorts of dangers are why pistol makers recommend factory loaded ammunition. I have an old .38 police special and would never think of using hand loads in it. But the .357's I had (they disappeared while I was concussed) I hand loaded maximum loads and hollowpoints so that it was a self protection gun.. I do not especially like automatic but that's the only way to get .380's and .40's which are good rounds that aren't likely to kill someone unless you hit them just right. |
#120
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casette shifting, again
On 12/19/2018 5:52 PM, John B. Slocomb wrote:
On Wed, 19 Dec 2018 09:20:10 -0800 (PST), wrote: On Monday, December 17, 2018 at 6:16:15 PM UTC-8, John B. Slocomb wrote: On Mon, 17 Dec 2018 15:41:14 -0800, "Mark J." wrote: On 12/15/2018 9:58 PM, John B. Slocomb wrote: On Sat, 15 Dec 2018 21:39:19 -0800 (PST), Sir Ridesalot wrote: On Saturday, December 15, 2018 at 10:43:29 PM UTC-5, John B. Slocomb wrote: On Sat, 15 Dec 2018 16:20:42 -0800 (PST), jbeattie wrote: On Saturday, December 15, 2018 at 1:59:24 PM UTC-8, AMuzi wrote: On 12/15/2018 3:04 PM, Emanuel Berg wrote: Frank Krygowski wrote: Emanuel, with all due respect, you should spend the winter reading a physics book or two. Or three. Skip the parts on electricity, atomic physics, etc. Concentrate on forces, motion, work, energy etc. - the parts that apply to bicycles. [...] Blah blah blah, you have told me this at least a dozen times by now. Probably because it is easier to be didactic/demeaning than to actually answer the questions. more. I left school without having slept through even one physics class. My reference work here is a 1955 high school textbook for $1 (9 Kr). I don't know all of even that, but I understand the world well enough to know that this headline last week: https://www.dailymail.co.uk/sciencet...soon-2022.html was completely ridiculous. The chamber pressures are in the same range, but not power, not even within a magnitude*! Power is work over time. Without some grasp of the actual world, you would not have laughed aloud when reading the headline, etc. *A typical 120mm tank round is 7.5 kilos of depleted uranium moving at 1700 m/s. The new 6.8 rifle typically moves 7.5 grams at 850 m/s. That's why you need basic physics. BTW, here's an interesting case that crossed my desk: https://www.bendbulletin.com/localst...killed-in-tank https://www.oregonlive.com/pacific-n...explosion.html Interesting object lesson for re-loaders. I'm representing a party on a collateral insurance issue. I've represented a couple big gun makers in over-pressure cases. Reloads. Too much powder or the wrong powder can blow-up guns large and small. -- Jay Beattie. One of the things I notices in the reference was that the gun had been "de-militarized" and that "was restored by Preston to working order". The term "de-militarized", at least as used by the U.S.A.F., means that the weapon is modified to a point that it cannot be fired, and cannot be repaired. In small arms usually by cutting the receiver and barrel into at least two parts, usually with a cutting torch. cheers, John B. I read the Preston put in 8oz. more powder than was the recommended load and was told that if he fired that cartridge it'd blow up the gun. Preston was also persuaded to take out more insurance due to that overloaded cartridge. Yes, I read that part too. I used to hand load for varmint rifles and of course we were always trying for that little extra speed, but we were also careful to inspect cartridge cases for signs of over pressure. I simply can't imagine anyone just shoveling in 8 ounces of extra powder. Particularly after someone "in the business" told not to. That extra 8 ounces blew my mind also. When I was maybe 30, I was helping my dad, a long-time pistol round reloader, mostly out of [my] curiosity. There was another seasoned reloader there also. I measured one shell's worth of powder and was surprised how excited they both got, exhorting me to avoid compressing or tamping down the powder ?while scooping? (details and wording are foggy years later). I was warned that any hint of ?compression? in the powder could result in a overload that could destroy a pistol. Who'd think you'd need to be careful working with explosives? Mark J. True. Gun powders are manufactured as grains and any packing or tamping down would allow more grains in the same space (measure). More explosive in the same place equals higher pressures. People that are loading right up to the maximum will weigh the powder rather then use a mechanical measure. cheers, John B. John - it wasn't until around WW I that bullets became supersonic. The is utter bull****. Between 1867 and 1900 there were at least 33 cartridges developed and marketed that were supersonic (speed of sound = 1125 ft/sec). There is an old saying, "Better to be silent and be thought a fool then to open one's mouth and prove it" that apparently you never heard. Or if you did you ignored it. example: http://gundata.org/cartridge/103/.45-70-government/ -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
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