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Pulsar Ballistics

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Re: Pulsar Ballistics
Post by Theemile   » Mon Nov 02, 2020 11:46 am

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TFLYTSNBN wrote:
Well this is disappointing. Only 2,000 meters per second muzzle velocity from a pulsar pistol. Heck, the sabot rounds from an Abrahms tank is about 1,400 meters per second.

It is interesting as well as easy to estimate the average recoil force from a full auto Pulsar. They come in various calibers and projectile masses. Assume a projectile mass of about 23 grains or about 1.5 grams, a muzzle velocity of 2,000 meters per second, and a fitting rate of 600 rounds per minute or 10 rounds per second.

The mass flow rate is then 15 grams per second or .015 kg per second. Multiply by muzzle velocity of 2,000 meters per second and you get a recoil force of 30 Newtons. This is the equivalent of a 3 kilogram weight in a one gee gravity field.



The firing concept might be conceptually the same as the American 180 - a light sub-machine gun firing .22 rimfire long rifle . the cyclic rate is insane -1200 rounds/min, and the gun carries as many as 250 rounds in drum magazines. Shooting one sounds like a rattle of angry bees, and the entire contents empties in seconds, and has little recoil and is very accurate at long pistol/short rifle ranges.

The overall concept is while 1 slug doesn't have that much energy or penetration, 40, fired in a quick accurate burst, do have alot of energy and will penetrate all the the most hardened armor.
******
RFC said "refitting a Beowulfan SD to Manticoran standards would be just as difficult as refitting a standard SLN SD to those standards. In other words, it would be cheaper and faster to build new ships."
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Re: Pulsar Ballistics
Post by jtg452   » Tue Nov 03, 2020 9:18 am

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TFLYTSNBN wrote:Well this is disappointing. Only 2,000 meters per second muzzle velocity from a pulsar pistol. Heck, the sabot rounds from an Abrahms tank is about 1,400 meters per second.

It is interesting as well as easy to estimate the average recoil force from a full auto Pulsar. They come in various calibers and projectile masses. Assume a projectile mass of about 23 grains or about 1.5 grams, a muzzle velocity of 2,000 meters per second, and a fitting rate of 600 rounds per minute or 10 rounds per second.

The mass flow rate is then 15 grams per second or .015 kg per second. Multiply by muzzle velocity of 2,000 meters per second and you get a recoil force of 30 Newtons. This is the equivalent of a 3 kilogram weight in a one gee gravity field.


Modern handgun ammunition rarely exceeds Mach 1.2 or 1.3 (14-1500fps), so a 4 fold increase in velocity would have a tremendous impact on any calculations.

On the other hand, RFC's pulsers are reliant on that velocity to do any sort of damage since the projectiles themselves are extremely light weight. Modern ammunition still has enough projectile weight that momentum retention has an impact on penetration. Mass (weight) retains momentum. Light weight bullets need higher velocities because they shed that momentum faster. A softball rolling on the ground can be stopped by putting your foot on it. Doing the same with a 4 pounder cannon ball leads to the loss of the foot.

Low velocity rounds as the 19th Century buffalo gun rounds (which had muzzle velocities equal to modern handgun rounds but were using bullets that weighed 4 times more) had such remarkable penetration abilities. Muzzle velocities of 12-1400fps were common- yet they were used to kill off the American bison to the point of extinction in little more than a decade.

Your own numbers quoted above put a pulser dart's weight at about 2/3 that of the most common .22LR bullet. At that weight, it had better have some serious velocity if it's going to have any sort of effectiveness down range.
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Re: Pulsar Ballistics
Post by Jonathan_S   » Tue Nov 03, 2020 10:25 am

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jtg452 wrote:
Modern handgun ammunition rarely exceeds Mach 1.2 or 1.3 (14-1500fps), so a 4 fold increase in velocity would have a tremendous impact on any calculations.

On the other hand, RFC's pulsers are reliant on that velocity to do any sort of damage since the projectiles themselves are extremely light weight. Modern ammunition still has enough projectile weight that momentum retention has an impact on penetration. Mass (weight) retains momentum. Light weight bullets need higher velocities because they shed that momentum faster. A softball rolling on the ground can be stopped by putting your foot on it. Doing the same with a 4 pounder cannon ball leads to the loss of the foot.

Low velocity rounds as the 19th Century buffalo gun rounds (which had muzzle velocities equal to modern handgun rounds but were using bullets that weighed 4 times more) had such remarkable penetration abilities. Muzzle velocities of 12-1400fps were common- yet they were used to kill off the American bison to the point of extinction in little more than a decade.

Your own numbers quoted above put a pulser dart's weight at about 2/3 that of the most common .22LR bullet. At that weight, it had better have some serious velocity if it's going to have any sort of effectiveness down range.

Well, reliant on velocity when shooting solid darts - they also have explosive darts; which wouldn't rely as much on velocity and terminal ballistics for damage.
Though in something as tiny as a pulsar sidearm's dart they'd probably need much a more powerful explosives that any explosive round/shell we have today in order to get any useful effect out of it.
On Basilisk Station wrote:his pulser turret was already in action, each barrel spitting fifteen-millimeter explosive darts cased in ceramic frag jackets at a cyclical rate of over a thousand rounds per minute.
Short Victorious War wrote:The carefully phrased "leaks" Jessup had arranged to test-flight the idea had provoked riots in virtually every Prole housing unit, and, two months later, Kanamashi had put twelve explosive pulser darts into Frankel's chest, requiring a closed-coffin state funeral.
Field of Dishonor wrote:Explosive darts ripped their way up the stairs the waiters had used—the stairs Nimitz would have used—and shredded the end of the dining platform, and Neufsteiler cried out as a jagged splinter drove into his back.
[...]A sawed-off pulse rifle flew through the air as LaFollet's target went down, but someone was still firing.
House of Steel wrote:The standard shoulder arm of the RMMC is the M32 series grav pulse rifle in 4 x 37 mm caliber. The M32A5, introduced in 1918 PD, is the latest variant of this versatile weapon system. The M32 has two magazine wells, each of which will accommodate a single hundred-round magazine. Pulser darts come in two basic varieties: a solid, non-explosive, antipersonnel round and a superdense, explosive round designed for antiarmor or general suppressive fire. A shorter carbine version, the M19, is designed for shipboard use. The standard sidearm carried by officers is the M7 pulser and its short-barreled variant the M9.
Cauldron of Ghosts wrote:The side hatch of a cargo van parked near the garage exit slid open as the limousine approached. The 10 mm heavy tri-barrel pulser positioned within the cargo compartment began firing as soon as the limousine came in sight. The weapon was firing super-dense 65 gram explosive rounds with a maximum rate of fire of up to 3,000 RPM (1,000 per barrel).
More Than Honor wrote:The pinnace screamed up in a near-vertical turn, passing near the scarred, smoking side of the Committee tower, then looped over again and began another run down the Avenue of the People. This time she was working from the rear of the crowd forward, towards the building the mob had hoped to overrun. To either side of her nose heavy tri-barrel pulsers raved in long spears of white light, sending thousands of heavy explosive projectiles down into the street below.
However I'm not sure if the pistol-sized pulsers have them too - in HotQ and SVW we get a couple explicit mentions of a pistol/sidearm pulser being loaded with or firing non-explosive darts. But I don't know if the reason non-explosive was explicitly mentioned was because they're also capable of firing explosive ones, or if that was just intended to contrast with the explosive dart ammo available for the larger pulser based weapon.
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Re: Pulsar Ballistics
Post by tlb   » Tue Nov 03, 2020 10:39 am

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jtg452 wrote:Modern handgun ammunition rarely exceeds Mach 1.2 or 1.3 (14-1500fps), so a 4 fold increase in velocity would have a tremendous impact on any calculations.

On the other hand, RFC's pulsers are reliant on that velocity to do any sort of damage since the projectiles themselves are extremely light weight. Modern ammunition still has enough projectile weight that momentum retention has an impact on penetration. Mass (weight) retains momentum. Light weight bullets need higher velocities because they shed that momentum faster. A softball rolling on the ground can be stopped by putting your foot on it. Doing the same with a 4 pounder cannon ball leads to the loss of the foot.

Low velocity rounds as the 19th Century buffalo gun rounds (which had muzzle velocities equal to modern handgun rounds but were using bullets that weighed 4 times more) had such remarkable penetration abilities. Muzzle velocities of 12-1400fps were common- yet they were used to kill off the American bison to the point of extinction in little more than a decade.

Your own numbers quoted above put a pulser dart's weight at about 2/3 that of the most common .22LR bullet. At that weight, it had better have some serious velocity if it's going to have any sort of effectiveness down range.

Jonathan_S wrote:Well, reliant on velocity when shooting solid darts - they also have explosive darts; which wouldn't rely as much on velocity and terminal ballistics for damage.
Though in something as tiny as a pulsar sidearm's dart they'd probably need much a more powerful explosives that any explosive round/shell we have today in order to get any useful effect out of it.
On Basilisk Station wrote:his pulser turret was already in action, each barrel spitting fifteen-millimeter explosive darts cased in ceramic frag jackets at a cyclical rate of over a thousand rounds per minute.
Short Victorious War wrote:The carefully phrased "leaks" Jessup had arranged to test-flight the idea had provoked riots in virtually every Prole housing unit, and, two months later, Kanamashi had put twelve explosive pulser darts into Frankel's chest, requiring a closed-coffin state funeral.
Field of Dishonor wrote:Explosive darts ripped their way up the stairs the waiters had used—the stairs Nimitz would have used—and shredded the end of the dining platform, and Neufsteiler cried out as a jagged splinter drove into his back.
[...]A sawed-off pulse rifle flew through the air as LaFollet's target went down, but someone was still firing.
House of Steel wrote:The standard shoulder arm of the RMMC is the M32 series grav pulse rifle in 4 x 37 mm caliber. The M32A5, introduced in 1918 PD, is the latest variant of this versatile weapon system. The M32 has two magazine wells, each of which will accommodate a single hundred-round magazine. Pulser darts come in two basic varieties: a solid, non-explosive, antipersonnel round and a superdense, explosive round designed for antiarmor or general suppressive fire. A shorter carbine version, the M19, is designed for shipboard use. The standard sidearm carried by officers is the M7 pulser and its short-barreled variant the M9.
Cauldron of Ghosts wrote:The side hatch of a cargo van parked near the garage exit slid open as the limousine approached. The 10 mm heavy tri-barrel pulser positioned within the cargo compartment began firing as soon as the limousine came in sight. The weapon was firing super-dense 65 gram explosive rounds with a maximum rate of fire of up to 3,000 RPM (1,000 per barrel).
However I'm not sure if the pistol-sized pulsers have them too - in HotQ and SVW we get a couple explicit mentions of a pistol/sidearm pulser being loaded with or firing non-explosive darts. But I don't know if the reason non-explosive was explicitly mentioned was because they're also capable of firing explosive ones, or if that was just intended to contrast with the explosive dart ammo available for the larger pulser based weapon.

Interesting that only the explosive rounds are described as super dense, while the others might be ceramic. Although a ceramic that incorporated osmium might be very dense also. However, as has been pointed out, anything too dense would make the extremely rapid fire difficult to control without some Honorverse "magic".

PS. I expect the police have explosive rounds available for the bigger guns in their rapid response squads, but not for general issue to cops on the beat.
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Re: Pulsar Ballistics
Post by Theemile   » Tue Nov 03, 2020 12:32 pm

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tlb wrote:Interesting that only the explosive rounds are described as super dense, while the others might be ceramic. Although a ceramic that incorporated osmium might be very dense also. However, as has been pointed out, anything too dense would make the extremely rapid fire difficult to control without some Honorverse "magic".

PS. I expect the police have explosive rounds available for the bigger guns in their rapid response squads, but not for general issue to cops on the beat.



a little more from Jayne's

M32A1 Pulse Rifle The standard shoulder arm of the RMMC is the M32A1 grav-pulse rifle in 4x37 mm caliber. The M32 has 2 magazine wells, each of which will accommodate a single 100-round magazine. A standard M13 power cell is inserted behind the magazines, and provides power for the weapon, targeting subsystem and any attachments.
Pulser darts come in two standard varieties: a solid, non-explosive, anti-personnel round and a super-dense, explosive round designed for anti-armor or general suppressive fire. The M32 is designed to accept one magazine of each and to switch back and forth between them at will. Conversely, the weapon may be loaded with 2 magazines of the same round, providing 200 rounds of fire without reloading.

The M32 operates as a linear-feed grav coil weapon, with few
moving parts aside from the magazine selection mechanism.
Muzzle velocity is adjustable up to a standard of 2,200 meters per second. The rate of fire is user configurable up to a maximum of 2500 RPM with a default setting of 400 RPM for full automatic fire and 2000 RPM for a 3-round burst.

The M76 Electronic Sight consists of a laser designator and
rangefinder, combination visual, IR and low-light sensor and a
multifunction display. Standard day mode is a reflex sight with an IR signature overlay for signatures above a preset threshold level. Additional modes are available for different attachments, such as the grenade launcher, with computed ranging, airburst and ballistic information relevant to the type of round being fired. The maximum effective range is 3,000 meters in one standard gravity, but opportunities to take advantage of such ranges are rare in combat.


also we saw a specialty anti-personnel "shredder" round, once - the Loomis Liberation Front was trying to block the import of these in Silesia.
******
RFC said "refitting a Beowulfan SD to Manticoran standards would be just as difficult as refitting a standard SLN SD to those standards. In other words, it would be cheaper and faster to build new ships."
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Re: Pulsar Ballistics
Post by jtg452   » Tue Nov 03, 2020 1:30 pm

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There's a whole school of red herrings around here, ain't there?

Must be those goal posts running a marathon that attracts them!

And look at all of those apples and oranges!

Sci-Fi explosive darts being compared to modern lead core rounds, pistol velocities compared to 120mm tank main guns, pistols to rifles,....

When ya'll pick one subject, I'll pipe back in.
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Re: Pulsar Ballistics
Post by tlb   » Tue Nov 03, 2020 1:42 pm

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jtg452 wrote:When ya'll pick one subject, I'll pipe back in.

Don't hold your breath, it is extremely rare for a thread to fail to explore side issues. Too bad in a way, because your post was useful. But you should have seen that coming in, since this thread already included comments on the prehistoric extinction of the mega-fauna in North America.
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Re: Pulsar Ballistics
Post by jtg452   » Tue Nov 03, 2020 2:00 pm

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tlb wrote:
jtg452 wrote:When ya'll pick one subject, I'll pipe back in.

Don't hold your breath, it is extremely rare for a thread to fail to explore side issues. Too bad in a way, because your post was useful. But you should have seen that coming in, since this thread already included comments on the prehistoric extinction of the mega-fauna in North America.

That's because I actually know something about firearms and ammunition. 40 years of handgun shooting and 25 years of competition and reloading gives you a good opportunity to learnca thing or two. According to a physicist of my acquaintance, I even have a pretty good layman's understanding of the physics of shooting and recoil.
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Re: Pulsar Ballistics
Post by TFLYTSNBN   » Wed Nov 04, 2020 3:42 am

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jtg452 wrote:
TFLYTSNBN wrote:Well this is disappointing. Only 2,000 meters per second muzzle velocity from a pulsar pistol. Heck, the sabot rounds from an Abrahms tank is about 1,400 meters per second.

It is interesting as well as easy to estimate the average recoil force from a full auto Pulsar. They come in various calibers and projectile masses. Assume a projectile mass of about 23 grains or about 1.5 grams, a muzzle velocity of 2,000 meters per second, and a fitting rate of 600 rounds per minute or 10 rounds per second.

The mass flow rate is then 15 grams per second or .015 kg per second. Multiply by muzzle velocity of 2,000 meters per second and you get a recoil force of 30 Newtons. This is the equivalent of a 3 kilogram weight in a one gee gravity field.


Modern handgun ammunition rarely exceeds Mach 1.2 or 1.3 (14-1500fps), so a 4 fold increase in velocity would have a tremendous impact on any calculations.

On the other hand, RFC's pulsers are reliant on that velocity to do any sort of damage since the projectiles themselves are extremely light weight. Modern ammunition still has enough projectile weight that momentum retention has an impact on penetration. Mass (weight) retains momentum. Light weight bullets need higher velocities because they shed that momentum faster. A softball rolling on the ground can be stopped by putting your foot on it. Doing the same with a 4 pounder cannon ball leads to the loss of the foot.

Low velocity rounds as the 19th Century buffalo gun rounds (which had muzzle velocities equal to modern handgun rounds but were using bullets that weighed 4 times more) had such remarkable penetration abilities. Muzzle velocities of 12-1400fps were common- yet they were used to kill off the American bison to the point of extinction in little more than a decade.

Your own numbers quoted above put a pulser dart's weight at about 2/3 that of the most common .22LR bullet. At that weight, it had better have some serious velocity if it's going to have any sort of effectiveness down range.


Projectile mass is important to achieve penetration, but it is the sectional density, not the mass, that combines with velocity to yield momentum density that dictates penetration.


Even at "only" 2,000 meters per second, those long, slender, Honorverse Pulsar darts have enough momentum density to penetrate a human torso from the top of the skull to the butt. In fact over penetration with minimal wounding from impacts at more normal aspects should be an issue. The only thing that makes these long, slender, hyper velocity pulsar days truly effective is the certainty that they will yaw upon impact. Weber mentions that pulsar days are son stabilized. I haven't calculated the skin rate needed to stabilize them, but it is extremely high. Imagine a 3mm x 25 mm dart yawing upon impact then tumbling at high rpm as it travels through a body like a buzz saw.

BTW, I'm one of the guys that writes the external ballistics programs that "gun experts" use to calculate trajectories as well as doing the internal ballistics calculations needed to determine what recipes are safe for hand reloading.
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Re: Pulsar Ballistics
Post by Daryl   » Wed Nov 04, 2020 5:34 am

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More than a decade ago my team was testing bullet proof vests for use in Army helicopter crews. One interesting point we discovered was that the same 5.56 mm or 0.223 military round would penetrate one brand if fired from a Steyr AUG, but not if fired from a M16. Turned out to be that the Steyr had tighter rifling which precluded tumbling when it hit the kevlar.
For comparison I took my 30.06 along. Didn't tell them that I was using black tip AP. Went through the front, through the optional ceramic plate, through the plasticine torso, out the rear and kept going.
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