John Kettler Posted June 3, 2003 Share Posted June 3, 2003 JonS, The collective name for such projectiles is dismantling shot, since their function is to dismantle the foe's rigging enough to prevent effective ship handling, thus allowing unhindered withdrawal, and sometimes, to inflict major damage by bringing down a mast and everything attached thereto. If you've ever seen a squarerigger, then you know that aloft is a veritable jungle of lines and blocks used to hold up the masts, pivot or secure the yardarms, hold up the yardarms, let out and take in sail, etc. Dismantling shot is a kind of scythe which cuts and breaks all it touches, turning complex systems into chaos and ruin. I believe a Google search under "naval artillery 18th century" would prove useful on this and other related matters. I highly recommend the Hornblower novels of C.S. Forrester and the Aubrey/Maturin novels of Patrick O'Brian as excellent and entertaining ways to grok naval warfare of the period. Ian Hogg wrote a book titled something like NAVIES OF THE AMERICAN REVOLUTION which had a whole page of illustrations of all manner of exotic and common dismantling shot. Regards, John Kettler 0 Quote Link to comment Share on other sites More sharing options...
Jeff Duquette Posted June 3, 2003 Share Posted June 3, 2003 A bit more from material generated during the hay-day of shrapnel shells. ============================================== "Shelter against shrapnel fire is secured by interposing obstacles between the source of fire and the target which stops or so reduces the velocity of the individual bullets that they are harmless. The shrapnel bullet is spherical and upon leaving the case has the remaining velocity of the projectile itself plus the velocity added to this by the bursting charge. The muzzle velocity of the projectile is 1700 feet per second. This velocity falls to 1000 feet per second at 2000 yards, and to 780 feet at 6000 yards. The velocity imparted by the bursting charge is about 200 feet per second. Therefore the velocity of the individual shrapnel bullet upon burst runs from 1200 feet per second at 2000 yards range to 980 feet per second at 5000 yards. These bullets are effective (have killing energy) against man and horse at distances varying from 220 to 175 yards from the point of burst between these ranges (2000-5000 yards). The efficiency of the shrapnel bullet is, therefore, not comparable to a modern rifle bullet but more to that of a 45 calibre pistol, and the necessary thickness and character of shelter may be gauged accordingly. Plank, boards, canvas, or brush with a few inches of earth thereon, tree trunks, etc., will generally constitute effective shelter from the shrapnel bullet. As to the danger space of the shrapnel bullet: To the angle of fall at any given range must be added the angle of opening made by the bullets in the lowermost element of the cone of dispersion. The angle of fall increases with the range, also the angle of the opening of the shrapnel. The following table shows the angle of fall of the bullets in the lowermost element of the shrapnel cone for several ranges. (Three inch gun.) Table… ============================================= The burst pattern of shrapnel was an irregular oval. The long axis of the burst zone is parallel to the direction of fire. The bursting charge was made from black powder as it produced a readily recognizable ball of smoke upon detonation. It made sensing ones own fire easier. In addition to what JonS has already astutely pointed out, part of the problem encountered in WW-I’ish shrapnel shell was apparently the slop involved with the fuse. Fuse accuracy I guess. Even if the appropriate range to target was known and fuse set to the appropriate range -- and all other potential error sources were eliminated from the equation – the shrapnel fuse was only accurate to within about 0.2 seconds. So on the extreme side of error…A projectile moving along at an average velocity of say 1500 m/s could travel 300 meters beyond the intended target before the fuse activated. Not a big deal to massed fires against troops in the open. Entrenched targets were a different matter. To be effective a shrapnel air burst has to be pretty close to directly over head when engaging targets hunkered down in an open trench. Combine this with the tendency of say mid-1915’ish plus Western Front infantry to sit out barrages in dugouts with over-head cover it is easy to understand why shrapnel rapidly declined in effectiveness and use. WW-I on the Eastern Front was much more fluid than the stagnant trench war being played out on the Western Front. Russian Artillerists were often confronted with massed formations of Austrian infantry…in the open. An ideal target for concentrated shrapnel fire. This combined with the rude handling of massed Russian infantry formations at the hands of Japanese Artillery firing shrapnel during the 1904-1905 war may have left a longer lasting impression as to the effectiveness of shrapnel within the Russian Army. I reckon this may have contributed to the lingering use of shrapnel against ground target on the part of the RKKA during WWII. 0 Quote Link to comment Share on other sites More sharing options...
flamingknives Posted June 3, 2003 Share Posted June 3, 2003 Every day's a school day. Good stuff in here. I thought I'd throw some stuff into the mix too. I've read of the use of case shot in the WWI tanks, from the 6 pdr sponson guns. It is described as a number of balls fixed to a length of wire. Sounds deeply unpleasant, but the sourcer doesn't really comment on its effectiveness. 0 Quote Link to comment Share on other sites More sharing options...
John D Salt Posted June 3, 2003 Share Posted June 3, 2003 Originally posted by rexford: In response to the following quote, go to the Panzer IV Universe site at http://ourworld.compuserve.com/homepages/willphelps/Specs-03.htm and you'll find that 75mm L24 fired case shot with 960 9mm balls. Excellent, thanks for that. So far, then, I am aware of the projectile numbers for the following canister rounds from WW2 to date: Soviet 45mm ATk: Shch-210 and -240 137 balls, Shch-243 ~105 balls Soviet 57mm ATk: Shch-271 324 balls 7.5cm L/24 KWK 37: Kt Kw K 960 balls US 37mm M6: Shot, Canister M2 122 balls US 57mm RCL M18: 133 slugs US 106mm RCL Beehive: 9,500 flechettes US 105mm Beehive: 6,000 flechettes US 152mm Shillelagh Beehive: 10,700 flechettes UK 76mm MV in Scorpion: 800 pellets The colossal increase in projectiles when flechettes are used in the beehive rounds is obvious. All the best, John. 0 Quote Link to comment Share on other sites More sharing options...
John D Salt Posted June 3, 2003 Share Posted June 3, 2003 Originally posted by John Kettler: [big snips] If grape is dismantling shot, then it is dismantling shot for people, not ships! Oops, you're quite right. I should perhaps have written "dis-mateloting shot". All the best, John. 0 Quote Link to comment Share on other sites More sharing options...
John D Salt Posted June 3, 2003 Share Posted June 3, 2003 Originally posted by JasonC: [big snips] Going back to the other round John was calculating things for, a quick and dirty "stepwise" bell would be to take the spread mentioned as roughly 2 SDs - 2/3s of the balls in the first half the radius (which is 1/4 the side to side area), the other 1/3rd in the remaining half the radius (which has 3/4 of the area). For those who are still interested in such things, I include some numbers from a version of the calculation refined along the lines suggested by Jason. It is pretty easy to set up a spreadsheet along these lines and fiddle about with different values of the parameters to see how they affect things. I've had a brief chat with a combat modelling pal from Fort Halstead, who sees nothing wrong with taking a man-sized target as 0.5 m^2 (rather smaller than the previous calculations). He also provided a "folk method" used for calulating P(hit) for short bursts, but it appears to break down for the large "burst" of 100+ projectiles in the sort of case we are interested in. As a crude piecewise approximation of a normal distribution, I have taken the circle formed by a section of the cone of fire at any range to be made up of four rings. The A ring subtends 0.1 radian, and contains 50% of the balls. The B ring subtends 0.2 radian, and contains a further 32% of the balls. The C ring subtends 0.3 radian, and contains a further 14% of the balls. The D ring subtends 0.4 radian, and contains the remaining 4% of the balls. So, with 0.1 radian fan angle per ring, and a 0.5 m^2 target area, we get the following P(hit)in each ring at different ranges in metres for the representative cases of 900, 600, 300 and 100 balls. They have been calculated up to the range where the P(hit) in the A (innermost) ring drops to 0.1. Depending on the mass and shape of the ball, pellet or slug, I think loss of velocity would remove most or all of the incapacitating effect at ranges around 500m. Balls_Range__A_____B_____C_____D 900____25___1.00__1.00__0.93__0.41 900____50___1.00__0.91__0.47__0.12 900___100___0.94__0.46__0.15__0.03 900___150___0.72__0.24__0.07__0.01 900___200___0.51__0.14__0.04__0.01 900___250___0.37__0.09__0.03__0.01 900___300___0.27__0.07__0.02__0.00 900___350___0.21__0.05__0.01__0.00 900___400___0.16__0.04__0.01__0.00 900___450___0.13__0.03__0.01__0.00 900___500___0.11__0.02__0.01__0.00 900___550___0.09__0.02__0.01__0.00 Balls_Range__A_____B_____C_____D 600____25___1.00__1.00__0.82__0.30 600____50___1.00__0.81__0.35__0.08 600___100___0.85__0.33__0.10__0.02 600___150___0.57__0.17__0.05__0.01 600___200___0.38__0.10__0.03__0.01 600___250___0.26__0.06__0.02__0.00 600___300___0.19__0.04__0.01__0.00 600___350___0.14__0.03__0.01__0.00 600___400___0.11__0.03__0.01__0.00 600___450___0.09__0.02__0.01__0.00 Balls_Range__A_____B_____C_____D 300____25___1.00__0.96__0.58__0.16 300____50___0.98__0.56__0.19__0.04 300___100___0.62__0.18__0.05__0.01 300___150___0.35__0.09__0.02__0.00 300___200___0.21__0.05__0.01__0.00 300___250___0.14__0.03__0.01__0.00 300___300___0.10__0.02__0.01__0.00 Balls_Range__A_____B_____C_____D 100____25___1.00__0.67__0.25__0.06 100____50___0.72__0.24__0.07__0.01 100___100___0.27__0.07__0.02__0.00 100___150___0.13__0.03__0.01__0.00 100___200___0.08__0.02__0.00__0.00 All the best, John. 0 Quote Link to comment Share on other sites More sharing options...
Amedeo Posted June 4, 2003 Share Posted June 4, 2003 Originally posted by John D Salt: So far, then, I am aware of the projectile numbers for the following canister rounds from WW2 to date: <cut> Go to this page and use canister and/or beehive as keywords for search in the NAME field. You'll find a few more rounds. Bye A. 0 Quote Link to comment Share on other sites More sharing options...
Jeff Duquette Posted June 4, 2003 Share Posted June 4, 2003 105mm M546 APERS-T is another example. APERS is more akin to shrapnel than canister. M546 is equipped with a time-fuse. The shell casing is designed for controlled fragmentation…4 fragments. The anti-personnel effect is created by six tiers of flechettes encased in the shell. There is a total of about 8,000 flechettes each weighing approx. 0.5g. The round is also equipped with a smoke-marker pellet to indicate point of detonation and ease the task of sensing ones own fire. Regarding High Explosive shell – circa-WWII US ARMY 105mm M38A1 HE will produce on average approx. 7,500 “effective” splinters from the uncontrolled fragmentation of the shell casing. The “effective” fragment weight ranges from 0.012-oz to 0.412-oz. and can generate casualties out to approx 600-ft from the burst. Effective fragment velocity ranges from ~2200-fps to ~400-fps. The burst pattern is also of some importance when determining the extent of “effective” fragments around the burst location. Killing effect doesn’t necessarily dissipate radially from the point of the shell burst. For example if the impact angle is about 30-deg the most lethal zone was apparently spread perpendicular to the line of fire. The most lethal zone sort of resembles a very elongated kidney bean emanating to either side of the line of fire. The shell detonation point is the the center of gravity -- so to speak -- of the kidney shaped fragmentation zone. [ June 03, 2003, 08:48 PM: Message edited by: Jeff Duquette ] 0 Quote Link to comment Share on other sites More sharing options...
rune Posted June 4, 2003 Share Posted June 4, 2003 From Valera's wonderful site, not much new here, but interesting none the less. Rune ORDER OF THE COMMANDER IN CHIEF OF THE FORCES OF WEST FRONT No.065 Concerning the employment of artillery shrapnel for the defeat of exposed enemy troops Secret 12 November 1941 Active Army Combat experience has shown that our artillerymen are completely inadequately employing shrapnel for defeat of exposed enemy troops, instead employing for this purpose projectiles with the fuse set for fragmentation action. The under appreciation of shrapnel can be explained only by the fact that young artillerymen do not know, and old artillery commanders have forgotten, that the shrapnel of 76mm regiment and division cannons when fired at exposed personnel at average ranges of 4-5 kilometers will cause twice the damage to a target as compared projectiles set for fragmentation action. The People's Commissar of Defense Comrade STALIN has pointed out this gross error in the combat activity of artillery in a special order and has demanded that it be immediately corrected. For the adoption of the broad and skillful use of shrapnel rounds in artillery units, I ORDER: 1. Explain to the command component and soldiers of artillery the valuable combat capabilities of shrapnel as a projectile intended for defeat of exposed enemy personnel, especially withering when fired for the destruction of attacking infantry and for self-defense against infantry. 2. Division artillery chiefs, commanders of artillery regiments and separate battalions are to confirm the knowledge of commanders of batteries that are equipped with the 76mm gun in the regulations for firing shrapnel and, when necessary, conduct practical exercises directly at observation posts in the techniques of conducting fire with shrapnel. 3. Require that 76mm gun batteries employ shrapnel in all cases of firing at exposed enemy troops, especially for the destruction of attacking infantry, self-defense against attacking infantry, for destruction of enemy observation posts sited in woods, and for clearing out of forested sectors. 4. Select commanders more capable and qualified in gunnery skills for the position of commander of 76mm batteries. 5. Maintain not less than 20 percent shrapnel munitions in the basic load of regiment and division artillery 76mm batteries. Report by telegraph to army military councils concerning the measures that are taken in compliance with this order. COMMANDER IN CHIEF OF FORCES OF WEST FRONT, ARMY GENERAL ZHUKOV MEMBER OF WEST FRONT MILITARY COUNCIL BULGANIN 0 Quote Link to comment Share on other sites More sharing options...
JonS Posted June 4, 2003 Share Posted June 4, 2003 A couple of resources related to Jeffs last post: M546 APERS-T 105-mm Graphic showing cut-aways of various projectile types, including the difference between Shrapnel, HE, and Cannister. Shape of fragmentation pattern. There is a useful description and two diagrams showing the 'kidney bean' that Jeff spoke of. Note that this is for HE fused PD. Airburst has a different pattern. Regards JonS 0 Quote Link to comment Share on other sites More sharing options...
Jeff Duquette Posted June 4, 2003 Share Posted June 4, 2003 Thanks for the link on M546. I almost thought I caught Janes in a boo-boo...after seeing the sectional drawing with 9-tiers of darts. I mis-read Janes it clearly indicates 9-tiers. According to Janes APERS was not only effective for close in defense. Although typically used in direct line of sight shoots, the projectile could apparently be tossed out to ranges of 9,500 to 12,400 meters dependent upon charge. The bursting charge fuse could be set for a minimum of 0.5 seconds for close in work\psudo-canister action or up to 100-seconds for more of a "sharpnel like" application. The following is an anecdote I came across somewhere on the web. Beehive in Vietnam... ============================================== "The exact results of the action will probably never be known; however, because of the damage done, the 3d Battalion, 2d North Vietnamese Army Regiment, avoided significant contact with allied forces for several months. The results were substantial considering there was no close contact between infantry units. Fire Support Surveillance Base FLOYD represented an economy-of-force measure employing a target acquisition system and immediate fire support in an interdiction mission. The terms "killer junior" and "killer senior" referred to direct fire defensive programs of the field artillery. Both techniques were designed to defend fire bases against enemy ground attack and used mechanical, time-fuzed projectiles set to burst approximately thirty feet off the ground at ranges of 100 to 1000 meters. The name "killer junior" applied to light and medium artillery (105-mm. and 155-mm.), while "killer senior" referred to the same system using eight-inch howitzers. This technique proved more effective in many instances than direct fire with "beehive" ammunition, because the enemy could avoid the beehive ammunition by lying prone or crawling. For example, in October 1967 during the battle of Xa Cat, which. involved an attack by several enemy battalions on the 1st Infantry Division's Fire Base CAISSON VI, artillery firing beehive ammunition had little effect on attacking enemy troops, because they approached the perimeter by crawling. However, a switch to timefuzed explosives stopped the advance. Another successful application of the "killer" technique was in clearing snipers from around base areas." 0 Quote Link to comment Share on other sites More sharing options...
John Kettler Posted June 4, 2003 Share Posted June 4, 2003 This thread just keeps getting better! Great stuff! John D. Salt, what an outstanding grognard pun! And now, to work. Thanks to Jeff Duquette's inputs we now know that U.S. shrapnel circa WWI used .45 cal balls, with a velocity at fuzing of some 1200 fps, dropping to about 800 several hundred yards later. Let's look at that. The lower velocity listed is only 30 fps lower than the muzzle velocity of the .45 ACP fired from the renowned U.S. M-1911A1 semiautomatic pistol. I take it no one here would dispute that weapon's reputation for manstopping, nor its ability out to tens of yards to pierce a typical combat helmet? I concede that the lower value definitely won't go through the trunk of any sort of substantial tree, but am not sure what might happen with a 50% delta vee in for targets right by the fuzing point. Since we're not dealing with a jacketed slug, but instead a semihardened or hardened lead ball, I think it's reasonable to assume that the shrapnel ball wouldn't penetrate as well as .45 ACP, both because of hardness differential and shape. With the above in mind, it seems to me that the next matter to attend to in our ongoing investigation is to find out what the individual shrapnel shot weighed and were shaped like for the various guns and countries of interest. We now apparently know how many shot were in each shrapnel round of interest, but we dare not assume standardization absent such evidence. IOTW, Russian 57mm shrapnel shot may well differ in size as well as projectile count from 76mm, because of differing packing constraints, say, but there are certainly limits imposed by target defeat criteria as well. Similarly, multiple nations may each have a unique shrapnel design while operating the same sized weapon. I continue to be impressed with the mathematical modeling work being done here. I fervently hope BFC is staying on top of this thread and doesn't release 1.03 until we've got this issue handled! Regards, John Kettler 0 Quote Link to comment Share on other sites More sharing options...
rexford Posted June 4, 2003 Share Posted June 4, 2003 Great work, John! Looking over the estimates I have a few notes and things to check: A. My hit probability calculation at 100m for 900 balls results in 100% within Ring A area, 61% within Ring B area, 16% within Ring C area and 3% within Ring D area. RING A AREA at 100m 79 m^2 area, 450 balls, 0.5m^2 target, 2.86 balls within target area on average RING B AREA at 100m 238 m^2 area, 288 balls, 0.5m^2 target, 0.61 balls within target area RING C AREA at 100m 401 m^2 area, 126 balls, 0.5m^2 target, 0.16 balls within target area RING D AREA at 100m 573 m^2 area, 36 balls, 0.5m^2 target, 0.03 balls within target area 2. From a simplistic standpoint, a shot with 300 balls should have one-third the hit probability of one with 900 balls if one is comparing balls per ring against ring area and target area, and 900 ball probability is less than 100%. At 300m, the 300 ball probability is about one-third the 900 ball figure, but at closer ranges the probability for 300 balls is much higher than one-third of 900 ball estimate. Could you explain the 100m calculations within each ring for the 300 ball case. Thank you. Lorrin Originally posted by John D Salt: </font><blockquote>quote:</font><hr />Originally posted by JasonC: . As a crude piecewise approximation of a normal distribution, I have taken the circle formed by a section of the cone of fire at any range to be made up of four rings. The A ring subtends 0.1 radian, and contains 50% of the balls. The B ring subtends 0.2 radian, and contains a further 32% of the balls. The C ring subtends 0.3 radian, and contains a further 14% of the balls. The D ring subtends 0.4 radian, and contains the remaining 4% of the balls. So, with 0.1 radian fan angle per ring, and a 0.5 m^2 target area, we get the following P(hit)in each ring at different ranges in metres for the representative cases of 900, 600, 300 and 100 balls. They have been calculated up to the range where the P(hit) in the A (innermost) ring drops to 0.1. Depending on the mass and shape of the ball, pellet or slug, I think loss of velocity would remove most or all of the incapacitating effect at ranges around 500m. Balls_Range__A_____B_____C_____D 900____25___1.00__1.00__0.93__0.41 900____50___1.00__0.91__0.47__0.12 900___100___0.94__0.46__0.15__0.03 900___150___0.72__0.24__0.07__0.01 900___200___0.51__0.14__0.04__0.01 900___250___0.37__0.09__0.03__0.01 900___300___0.27__0.07__0.02__0.00 900___350___0.21__0.05__0.01__0.00 900___400___0.16__0.04__0.01__0.00 900___450___0.13__0.03__0.01__0.00 900___500___0.11__0.02__0.01__0.00 900___550___0.09__0.02__0.01__0.00 Balls_Range__A_____B_____C_____D 600____25___1.00__1.00__0.82__0.30 600____50___1.00__0.81__0.35__0.08 600___100___0.85__0.33__0.10__0.02 600___150___0.57__0.17__0.05__0.01 600___200___0.38__0.10__0.03__0.01 600___250___0.26__0.06__0.02__0.00 600___300___0.19__0.04__0.01__0.00 600___350___0.14__0.03__0.01__0.00 600___400___0.11__0.03__0.01__0.00 600___450___0.09__0.02__0.01__0.00 Balls_Range__A_____B_____C_____D 300____25___1.00__0.96__0.58__0.16 300____50___0.98__0.56__0.19__0.04 300___100___0.62__0.18__0.05__0.01 300___150___0.35__0.09__0.02__0.00 300___200___0.21__0.05__0.01__0.00 300___250___0.14__0.03__0.01__0.00 300___300___0.10__0.02__0.01__0.00 Balls_Range__A_____B_____C_____D 100____25___1.00__0.67__0.25__0.06 100____50___0.72__0.24__0.07__0.01 100___100___0.27__0.07__0.02__0.00 100___150___0.13__0.03__0.01__0.00 100___200___0.08__0.02__0.00__0.00 All the best, John. </font> 0 Quote Link to comment Share on other sites More sharing options...
John Kettler Posted June 4, 2003 Share Posted June 4, 2003 On further thought, I've decided that we have another problem which needs to be addressed. The velocities, 800 and 1200 fps previously quoted, were for 5000 and 2000 yard fuzing ranges, but we need to reconsider the vastly more unpleasant for the recipient case of 1700 fps muzzle velocity and 200 fps for the shrapnel's burst, for a total of 1900 fps, a substantial jump in kinetic energy over even the 2000 yard case. Assuming I didn't screw up the calculation, by my math a near muzzle burst will yield a whopping 5.64 times greater kinetic energy in each shrapnel ball than would be the case at 5000 yards and 2.51 times more than at 2000 yards. This may or may not change the ball's ability to get through tree trunks, but it absolutely will strongly affect the secondary missile issue and the argued utility of lighter cover. Conceivably, we may also be looking at multiple casualties from a single shrapnel ball. Though I don't have the muzzle velocity numbers handy for the T-34 cannon whose mighty (and presumed excessive?) smitings started this thread, I suspect that the numbers are higher than the WW I era U.S. field artillery piece, making my musings conservative by definition. I'll close by adding that I erred somewhat in broadly using the term shrapnel in my prior post. Frankly, I'm still processing the multifunction Russian 76mm round and got somewhat distracted. It really shouldn't have disturbed me, though, for the U.S. 105mm APERS-T round had exactly the same kind of fuzing options, and it was the round of choice for dealing with an antitank guided missile (ATGM) launch--from both the huge intimidation factor and the vast amount of dust it threw up. Back when this was the immediate action drill, ATGMs had to be flown manually to the target using a joystick. Making the soldier controlling the ATGM flinch was enough to cause an outright miss or frequently a crash. As for artillery fired flechette ammo in direct defense, I distinctly remember a Vietnam War LIFE magazine piece in which a firebase was being overrun and the "Beehive" warning was given shortly before the 105mm howitzers were fired at zero elevation into the swarming enemy soldiers. Not only was the attack broken, but patrols reported finding "VC pinned to trees." Regards, John Kettler 0 Quote Link to comment Share on other sites More sharing options...
John D Salt Posted June 4, 2003 Share Posted June 4, 2003 Originally posted by rexford: [snips] Looking over the estimates I have a few notes and things to check: A. My hit probability calculation at 100m for 900 balls results in 100% within Ring A area, 61% within Ring B area, 16% within Ring C area and 3% within Ring D area. ISTM that you are calculating the mean number of balls per target. That is a rather different thing from P(hit), which is the probability that a given target will be hit by one or more balls. The probability of a target being hit by a single ball is obviously the same as the expected number of balls per target for one ball: p = 1/(a/t) Where p = hit probability (= balls per target in this case only), a = area of ring, and t = area of target (man). The probability of a target being missed is, obviously, one minus the hit probability. I assume (for simplicity) that the probability of being hit by any given ball is independent of the probability of being hit by any other ball. So, if a target (man) has a probability x of being missed by one ball, he will have a chance x^2 of being missed by two, x^3 of being missed by three, and so on (the increasing powers giving decreasing probabilities, as the probabilities are numbers smaller than one). Remembering that miss probability is one minus the hit probability, the probability, h, of an individual man being hit by some number of balls, b, is given by one minus the probability of an individual ball missing (1 - p), raised to the power of the number of balls, b. h = 1 - ((1-p) ^ or, more colloquially, one minus P(miss) to the power of balls. Originally posted by rexford: 2. From a simplistic standpoint, a shot with 300 balls should have one-third the hit probability of one with 900 balls if one is comparing balls per ring against ring area and target area, and 900 ball probability is less than 100%. At 300m, the 300 ball probability is about one-third the 900 ball figure, but at closer ranges the probability for 300 balls is much higher than one-third of 900 ball estimate. Could you explain the 100m calculations within each ring for the 300 ball case. I hope the above explanation has shown why this should be so. At 300m, the pattern of projectiles has thinned out to the point where the P(hit) and balls-per-target figures are not too far apart. At 100m, many of the targets hit will be hit by more than one ball, and it is this "over-hitting" effect that accounts for the wide difference between P(hit) and balls-per-target. Increasing the number of balls from 300 to 900 when P(hit) is already high will result in a small increase in P(hit) and a large increase in over-hitting. Apologies if this isn't clear -- these things are so much easier to explain around a whiteboard. All the best, John. [ June 04, 2003, 06:55 AM: Message edited by: John D Salt ] 0 Quote Link to comment Share on other sites More sharing options...
rexford Posted June 4, 2003 Share Posted June 4, 2003 One of my previous posts on this thread presented the muzzle velocity for Russian 76.2mm schrapnel from field guns, which ranged from 626 m/s at normal charge to 474 m/s at reduced charge. My past post also gave into on the Mundungwucht and Gasdruck (at). I also offered to share scans of the German drawings and firing tables for Russian 76.2mm schrapnel, which can be used to determine velocity at range, length of the ground hits, etc., but no one took me up on the offer. 0 Quote Link to comment Share on other sites More sharing options...
JasonC Posted June 4, 2003 Share Posted June 4, 2003 Then to get expected hits, you have to multiply the percent chance at a given range by the number of men within the arc at that range. At 50m, with the width of your categories, that is just the numbers in your charts, for 5m spacing. At 100m, twice the number in your charts. At 25m, half. At 200m, four times. Etc. Thus - Balls_Range__A_____B_____C_____D 900____25___1.00__1.00__0.94__0.41 = 1.67 900____50___1.00__0.91__0.47__0.12 = 2.50 900___100___0.94__0.46__0.15__0.03 = 3.16 900___200___0.51__0.14__0.04__0.01 = 2.80 900___400___0.16__0.04__0.01__0.00 = 1.68 Balls_Range__A_____B_____C_____D 300____25___1.00__0.96__0.58__0.16 = 1.35 300____50___0.98__0.56__0.19__0.04 = 1.77 300___100___0.62__0.18__0.05__0.01 = 1.72 300___200___0.21__0.05__0.01__0.00 = 1.08 The number hit is low at first because there just aren't many men within the cone. It then rises as more men "enter", while the density remains high. Then the density of ball falls off, and the chance of each man surviving increases, counteracting the rise from more men within the cone. The maximum values are seen around 50-100m from the burst point. A larger number of balls naturally makes the distance for maximum probable hits farther from the burst point, as it takes longer for the denser spread to widen enough. Note also that the rise in expected hits goes less than linear, basically square root, of the number of balls. 3.16/1.77 = 1.79, 3^.5 = 1.73. If you double the number of men in the cone, naturally you double the number of expected hits. If instead you reduce the spacing to 2.5m but then have the number of men top out at 10, you have a target 25m wide. Assuming the cone is centered correctly, that means you throw out bits of the tails while keeping an "amplified" center section (amplified for smaller, 2.5m spacing). Balls_Range__A_____B_____C_____D 900____25___1.00__1.00__0.94__0.41 = 3.34 900____50___1.00__0.91__0.47__0.12 = 5.00 900___100___0.94__0.46__0.15__0.03 = 5.90 900___200___0.51__0.14__0.04__0.01 = 4.36 900___400___0.16__0.04__0.01__0.00 = 1.60 Balls_Range__A_____B_____C_____D 300____25___1.00__0.96__0.58__0.16 = 2.70 300____50___0.98__0.56__0.19__0.04 = 3.54 300___100___0.62__0.18__0.05__0.01 = 3.30 300___200___0.21__0.05__0.01__0.00 = 1.78 Because you have 1x each number with 4 men within the cone, then 2x each with 8 men within, then 4x, 4x, 2x, 0x as all 10 fit inside, most in the first 2 categories, then 8x, 2x, 0x, 0x as most of a squad fits within A at 200m. With tight spacing, perfect range, and no cover, the 900 might hit 6, while the 300 might hit 3-4. If you reduce those for 70% exposure (CMBBs open ground cover estimate), 2 1/2 and 4 men are the likely hits for perfect range, squad target with tight spacing, open ground. Building or woods cover at CMBB exposure numbers ought to reduce the men hit to 1-2. Either cover or wide spacing provide decent overall protection against individual canister rounds. You wouldn't want to lose that many men to each shell all day, but whole squads evaporating to single shots while inside stone buildings is way off. The numbers are in fact pretty much what close range squad fire does in CMBB today. I mean a full strength squad shooting at men in the open sometimes blows away half the unit in a burst, while in cover it typically picks off a man or two with each shot, running through them in a minute or two but not in one burst. A 900 ball canister round could be like 400 FP (akin to an SMG squad), while a 360 ball shrapnel fired as canister Russian 76 could be 250 FP (.4 times number of ball, square root, implies 63% of the FP). The FP should go as the square root of the number of ball in the round. Present canister fire is too strong, particularly against targets in cover. An FP based solution with FP numbers in the same range as well armed full squads would give the right tactical impact. John's spreadsheet calculations support that. 0 Quote Link to comment Share on other sites More sharing options...
flamingknives Posted June 4, 2003 Share Posted June 4, 2003 Can you post them on the site rexford? Failing that, email them to me (in the profile) and I'll put them up. (provided they don't take up more than about 1MB (Dial-up internet. Grrr.) 0 Quote Link to comment Share on other sites More sharing options...
John D Salt Posted June 4, 2003 Share Posted June 4, 2003 Originally posted by JasonC: [snips] With tight spacing, perfect range, and no cover, the 900 might hit 6, while the 300 might hit 3-4. If you reduce those for 70% exposure (CMBBs open ground cover estimate), 2 1/2 and 4 men are the likely hits for perfect range, squad target with tight spacing, open ground. Building or woods cover at CMBB exposure numbers ought to reduce the men hit to 1-2. Either cover or wide spacing provide decent overall protection against individual canister rounds. You wouldn't want to lose that many men to each shell all day, but whole squads evaporating to single shots while inside stone buildings is way off. Rather than multiply the final casualty figures by an exposure percentage, it will cause less distortion simply to adjust the assumed target area of each man to get different figures from the spreadsheet. One might argue that the 0.5 m^2 target area already reflects a 0.75 m^2 strapping chap with typical terrain masking taken into account. If one wanted a more refined model, it might be claimed that the amount of terrain masking for any given "crinkliness" of terrain will increase with range -- with, perhaps, a slight reduction for bullet-drop. If troops are protected by cover that is proof against the projectiles, then the casualties will reduced depending on how much they expose themselves. If we assume a target area of 0.1 m^2, then the hit probabilties for the 900-ball case look like this: Balls_Range__A_____B_____C_____D 900____25___1.00__0.86__0.40__0.10 900____50___0.90__0.39__0.12__0.03 900___100___0.44__0.12__0.03__0.01 900___150___0.22__0.05__0.01__0.00 900___200___0.13__0.03__0.01__0.00 900___250___0.09__0.02__0.01__0.00 900___300___0.06__0.01__0.00__0.00 ...still pretty devastating at the very close ranges, and while the effectiveness is much reduced, it drops rather less that in proportion the reduction in target area, because the degree of over-hitting is reduced too. Obviously, if troops are not putting their heads up at all (I don't know at what level of suppression CM considers this to happen) and are behind bullet-proof cover, then they should suffer no casualties at all. I have the impression that CM currently inflicts losses on troops I would imagine to be effectively invulnerable to bullet fire, e.g. those crouching at the bottom of trenches. All the best, John. All the best, John. 0 Quote Link to comment Share on other sites More sharing options...
JasonC Posted June 4, 2003 Share Posted June 4, 2003 That's fine for exposures, but does not leave a "still pretty devasting" result. Because all the .86-.9 numbers are for 5m wide areas (A at 50m or B at 25m e.g.), and the .39-.44 numbers are for 10m wide areas. Meaning you are talking about hitting the man aimed at, and maybe getting someone beside him. The cone is just too small in the A or B plus close range categories. It is of course not surprising that if you point a cannon at a guy you can kill that guy. If he were inside a brick building giving him complete cover you'd still get him if the round were HE instead of canister - and have a decent chance at anyone 5m away from him. 0 Quote Link to comment Share on other sites More sharing options...
rune Posted June 4, 2003 Share Posted June 4, 2003 Found the following information: The F-34 gun was 42 calibers long and fired a BR-350A armor piercing projectile, an OF-350 high explosive shell, or a SH-350 shrapnel round, stowed in the tank in a ratio of 19/53/5, as indicated in a 1942 summer report Source: http://www.kithobbyist.com/AFVInteriors/t34/t34b.html Also trying to email Valera, due to the fact I know he insisted there was a different cannister round. Trying to get more from him. Rune 0 Quote Link to comment Share on other sites More sharing options...
Wilhammer Posted June 4, 2003 Share Posted June 4, 2003 You guys are amazing... The ultimate expression in 'Beehive' round size was achieved thus: "One very fascinating factor about the ammunition: since Japan suffered heavy losses in her naval aviation community early in the war, capital ships were expected to provide their own defense against allied aircraft. As a result of this, the 18-inch gun was provided with an anti-aircraft shell of its own, called "San Shiki" (the Beehive)Model 13. This round weighed 2,998 pounds and was filled with 900 incendiary tubes (of rubber thermite) and 600 steel stays. A time fuze was supplied, set before firing, that went off at a predetermined altitude and when the fuze functioned, the explosive and metal contents burst in a cone extending 20 degrees forward, towards the oncoming aircraft. Instantly after detonating, the projectile shell itself was destroyed by a bursting charge, increasing the quantity of steel splinters. The incendiary tubes ignited about half a second later and burned for five seconds at 3000 degrees C, producing a flame about 16 feet long. 0 Quote Link to comment Share on other sites More sharing options...
rune Posted June 4, 2003 Share Posted June 4, 2003 I found this old note from Valera... The Sovet 76-mm Case-Shot Round She-350 consisted of 549 bullets, 10 grammes each bullet. When fired, bullets scattered at angle 6-9 degrees. Since the effective killing range (distance)* was about 200 metres, the maximum scatter range was ~50 metres. *This means a 90% probability to kill any unprotected man. This sounds much different then the shrapnel rounds being talked about in the 1938 report. Still trying to get more information from him. Rune 0 Quote Link to comment Share on other sites More sharing options...
SFJaykey Posted June 4, 2003 Share Posted June 4, 2003 Originally posted by Wilhammer: The ultimate expression in 'Beehive' round size was achieved thus: "One very fascinating factor about the ammunition: since Japan suffered heavy losses in her naval aviation community early in the war, capital ships were expected to provide their own defense against allied aircraft. As a result of this, the 18-inch gun was provided with an anti-aircraft shell of its own, called "San Shiki" (the Beehive)Model 13...... Ultimate, except for one thing: when actually employed against US aircraft, at Leyte and Okinawa IIRC, the effect was nil. I'm sure that watching the Helldivers fly through it took the wind out of many an Imperial sailor. Which raises a question: the Soviet artilleryman who commented on the devastating effect of cannister admitted, if I'm reading correctly, that he had never fired the round in combat. Perhaps the "devastating" effects were played up in training, to instill some confidence in artillerymen facing an infantry charge...just as the Sanshiki shell bouyed Japanese naval hopes. 0 Quote Link to comment Share on other sites More sharing options...
Jeff Duquette Posted June 5, 2003 Share Posted June 5, 2003 Couple quick notes on RKKA WWII 76,2mm shrapnel. References I have access to indicate lead pellets\balls; about 11-grams per ball. The images are a bit rough but if I had to hazard a guess I would say dia was about 8 or 12 mm. About 600 balls per round (this is up from WWI’ish 76mm shrapnel shells used by the Russian Army -- ~260 larger dia balls in WWI shells). Bursting charge results in uncontrolled fragmentation of the shell casing. This adds additional splinters into the mix. Several images I have of fragments and pellets collected in controlled environment indicate fragmentation of the casing results in relatively large splinters…two such images yield an additional 50 to 70 splinters from the fragmentation of the shell casing. Combat load for a 76mm Divisional Gun: Battery limbers\wagons 212 rounds\gun Regimental Train: 96 rounds\gun Divisional + Corps Artillery Train 300 rounds\gun Combat load was about half the above by 1943. Typical distribution of Ammunition for 76mm gun (from 1936): 30% H.E. 30% Shrapnel 30% Gas 5% Incendiary 5% Star Shell The RKKA’s use of Shrapnel against ground targets seems to have been quite prevalent during WWII. And given the right circumstances, could be fairly effective. However manufacturing cost of shrapnel was considerably higher than the cost of HE shell of the same caliber. 0 Quote Link to comment Share on other sites More sharing options...
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