Guest pfcem Posted September 18, 2005 Posted September 18, 2005 While mv is important to the penetration performance of an APFSDS, there are a lot of other factors as well. One factor that is very difficult to calculate the material of the penetrator itself. With all other factors being similar, DU is believed to produce 10-15% better penetration capabilities over Tungsten. Of coarse the latest generation of penetrators (whether DU or Tungsten) are actually made up of alloys & aside from those responsible for developing & testing these penetrators, I doubt anybody knows what they are actually made of & how that material performs compared to other penetrator materials. The M829 reportedly had a mv of around 1680m/s. The M829A1 reportedly had a mv of 1575m/s (about 100m/s slower) yet had around a 10% increase in armor penetration over the m829. The M829A2 reportedly has a mv of 1680m/s (100m/s faster than the M829A1 & about the same as the M829) with around a 20% increase in armor penetration over the m829A1. Now the M829A3 reprtedly has a mv of 1555m/s (about the same as the M829A1 but with a penetrator at least 1kg heavier) with speculation of anywhere beween 10-30% increase in armor penetration over the m829A2. Another thing to remember is that a heavier penetrator (like the M829A3) is going to maintain a greater % of its muzzle energy at longer ranges so the M829A3 may have only a 10% increase in penetration over the M829A2 at the muzzle but 30% or more at 3km or more.
jwduquette1 Posted September 19, 2005 Posted September 19, 2005 It is indicated? Why don't you ask some TN members. I'm sure they/we/I can state catagorically, and from first hand experience, that M829A1 was used during ODS, if in limited supply. As a side note. The M829A1 received the moniker 'silver bullet' because the windscreen is in fact silver in color. That the cure for several VDs is penicillin, which is also known as a 'silver bullet', is not coincidental.223871[/snapback] Hello DkTanker: Thanks for confirming. Frankly I thought attendance at this corner of TankNet was rather limited. I figured if I asked the question, it would go unanswered, and the only source I could lay hands on at that moment was Janes. Regarding Silver Bullet – what about the Lone Ranger? Or the projectile required for dispatching Werewolves (or is it vampires?). Coors Light was just a reflection of my beercentricity. I suppose I should be ashamed of the fact that I actually like Coors Light -- but I'm not. I do have an additional question (perhaps a goofy question), but do recall ever seeing M829 or M829A1 ricochet off of an Iraqi tank? Same question for 120mm HEAT? Best RegardsJD
Paul Lakowski Posted September 19, 2005 Posted September 19, 2005 If the rod is 25mm thick and 800mm long then the volume is around 390cc. Based on a DU alloy of 18.6g/cc density, this leads to a mass of around 7 kg!!! Most such APFSDS are around ~5Kg. I suspect the 25mm refers to the outer nose which is often covered in several mm of aluminum to limit/prevent DU contamination? My estimate based on the 78cm x 21.5mm was.... The penetrator is reported to be longer than the M-829A2 and improved DU alloy [DU-V? ] , but it may be the same mass combined with increased striking velocity based on the following figures : 740mm x 21.5mm penetrator, with a 4cm nose plug: 5.1kg mass with a L/D ratio: 37.0:1 Muzzle velocity: 1555m/s with a V drop better than M-829A2 or about 50-55km/s/km . Anderson formula suggests 1.044 V - 0.92 [L/d] x 1.17 [scaling] x 1.13 [DU] x 1.2 if DU-V included and “back plate effect” [@ 0°/60°] is +1d @ 0° & +2d @ 60° or + 2.05cm @ 0° and 60° . The estimated penetration should be….. Muzzle [1555m/s] = 1.12 x 78cm = 87cm + 2.05cm = 89cm ± 13cm @ 0° & 45.6cm ± 7cm@ 60°1000m [1500m/s ]= 1.02 x 78cm = 79.9 cm + 2.05cm = 82cm ± 13cm @ 0° & 42cm ± 6cm@ 60°2000m [1450m/s] = 0.94 x 78cm = 73..5cm + 2.05cm = 75.5cm ± 14cm @ 0° & 38.8cm ± 7cm@ 60°3000m [1400m/s] = 0.86 x 78cm = 67.0cm + 2.05cm = 69cm ± 13cm @ 0° & 35.6cm ± 7cm@ 60°4000m [1350m/s] = 0.77 x 78cm = 60.6 cm + 2.05cm = 63cm ± 13cm @ 0° & 32.3cm ± 6cm@ 60° If infact the penetrator is longer that will increase penetration.
jwduquette1 Posted September 20, 2005 Posted September 20, 2005 If the rod is 25mm thick and 800mm long then the volume is around 390cc. Based on a DU alloy of 18.6g/cc density, this leads to a mass of around 7 kg!!! Most such APFSDS are around ~5Kg. I suspect the 25mm refers to the outer nose which is often covered in several mm of aluminum to limit/prevent DU contamination? My estimate based on the 78cm x 21.5mm was....The penetrator is reported to be longer than the M-829A2 and improved DU alloy [DU-V? ] , but it may be the same mass combined with increased striking velocity based on the following figures : 740mm x 21.5mm penetrator, with a 4cm nose plug: 5.1kg mass with a L/D ratio: 37.0:1 Muzzle velocity: 1555m/s with a V drop better than M-829A2 or about 50-55km/s/km . Anderson formula suggests 1.044 V - 0.92 [L/d] x 1.17 [scaling] x 1.13 [DU] x 1.2 if DU-V included and “back plate effect” [@ 0°/60°] is +1d @ 0° & +2d @ 60° or + 2.05cm @ 0° and 60° . The estimated penetration should be….. Muzzle [1555m/s] = 1.12 x 78cm = 87cm + 2.05cm = 89cm ± 13cm @ 0° & 45.6cm ± 7cm@ 60°1000m [1500m/s ]= 1.02 x 78cm = 79.9 cm + 2.05cm = 82cm ± 13cm @ 0° & 42cm ± 6cm@ 60°2000m [1450m/s] = 0.94 x 78cm = 73..5cm + 2.05cm = 75.5cm ± 14cm @ 0° & 38.8cm ± 7cm@ 60°3000m [1400m/s] = 0.86 x 78cm = 67.0cm + 2.05cm = 69cm ± 13cm @ 0° & 35.6cm ± 7cm@ 60°4000m [1350m/s] = 0.77 x 78cm = 60.6 cm + 2.05cm = 63cm ± 13cm @ 0° & 32.3cm ± 6cm@ 60° If infact the penetrator is longer that will increase penetration.224411[/snapback] Hi Paul: Your modifications of Anderson’s simple L/D effect equation never seemingly yield repeatable results. For example your previous estimations for M829A3 on YahooTankers are based upon the same rod Geometry. However this previous estimate was based upon a much higher muzzle velocity. You had assumed Mv=1830m/s. What is interesting about your previous January estimates for YahooTankers is that it included the following: [1590m/s] = 1.03 x 78cm = 80.3 cm + 2.05cm = 84cm ± 13cm @ 0° & 42cm ± 6cm@ 60° Your new estimates based upon an Mv = 1555m/s has the following: [1555m/s] = 1.12 x 78cm = 87cm + 2.05cm = 89cm ± 13cm @ 0° & 45.6cm ± 7cm@ 60° So while the rod geometry hasn’t changed from your previous set of estimates, the 0-degree perforation magnitude for your 1590m/s velocity figure is something like 50mm lower than your new estimate for a remaining velocity of only 1555m/s. RegardsJD
Paul Lakowski Posted September 20, 2005 Posted September 20, 2005 Hi Paul: Your modifications of Anderson’s simple L/D effect equation never seemingly yield repeatable results. For example your previous estimations for M829A3 on YahooTankers are based upon the same rod Geometry. However this previous estimate was based upon a much higher muzzle velocity. You had assumed Mv=1830m/s. What is interesting about your previous January estimates for YahooTankers is that it included the following: [1590m/s] = 1.03 x 78cm = 80.3 cm + 2.05cm = 84cm ± 13cm @ 0° & 42cm ± 6cm@ 60° Your new estimates based upon an Mv = 1555m/s has the following: [1555m/s] = 1.12 x 78cm = 87cm + 2.05cm = 89cm ± 13cm @ 0° & 45.6cm ± 7cm@ 60° So while the rod geometry hasn’t changed from your previous set of estimates, the 0-degree perforation magnitude for your 1590m/s velocity figure is something like 50mm lower than your new estimate for a remaining velocity of only 1555m/s. RegardsJD224510[/snapback] Hi Jeff, thanks for pointing that out. I tracked down the error to my improvised DUV modifiction. We originally estimated 20% improvement for DUV over WHA as compared to 8-13% from DU over WHA. When I redid the file , in my hast I multipled my DU modifer by the DUV modification adding error instead of either/or We really really need a seperate formula for DU penetration . The revised figures are as follows.... Muzzle [1555m/s] = 1.01 x 78cm = 78.6 cm + 2.15cm = 81cm ± 12cm @ 0° & 41cm ± 6cm@ 60°1000m [1500m/s ]= 0.93 x 78cm = 73..5cm + 2.15cm = 75cm ± 11cm @ 0° & 38cm ± 6cm@ 60°2000m [1450m/s] = 0.86 x 78cm = 67.0cm + 2.15cm = 69cm ± 10cm @ 0° & 36cm ± 5cm@ 60°3000m [1400m/s] = 0.78 x 78cm = 60.8 cm + 2.15cm = 63cm ± 9cm @ 0° & 33cm ± 5cm@ 60°4000m [1350m/s] = 0.71 x 78cm = 55.6 cm + 2.15cm = 58cm ± 9cm @ 0° & 30cm ± 4cm@ 60° Rod may well be 80cm long resulting in the following penetration figuresMuzzle [1555m/s] = 1.01 x 80cm = 80.8 cm + 2.15cm = 83cm ± 12cm @ 0° & 42.5cm ± 6cm@ 60°1000m [1500m/s ]= 0.93 x 80cm = 74.6 cm + 2.15cm = 77cm ± 11cm @ 0° & 39cm ± 6cm@ 60°2000m [1450m/s] = 0.86 x 80cm = 69 cm + 2.15cm = 71cm ± 10cm @ 0° & 36cm ± 5cm@ 60°3000m [1400m/s] = 0.79 x 80cm = 63 cm + 2.15cm = 65cm ± 9cm @ 0° & 34cm ± 5cm@ 60°4000m [1350m/s] = 0.71 x 80cm = 57 cm + 2.15cm = 59cm ± 9cm @ 0° & 31cm ± 4cm@ 60° It looks like DM-53 and M-829A3 are pretty much the same penetration. I hear their is a M-829A4, given the gap between what the penetration of the M-829A3 was thought to be and what it turns out to be, perhaps the newer model is not as much as of a surprise. Any one seen or heard any figures/info on the new M-829A4 APFSDS?
Guest pfcem Posted September 20, 2005 Posted September 20, 2005 224545[/snapback] Your post is the 1st I have ever heard of a possible M829A4. Do your calculations take into account that the M829A3 is undoubtably made of a material superior to that of the M829A2? Could you provide your latest calculations for the M829A1 & M829A2?How about the calculation for the British, German, French & other rounds as well? Most "reliable" sources give a penetration a value for the M829A1 at anywhere between 600-650mm@2000m & a penetration a value for the M829A2 at anywhere between 700-750mm@2000m. Based on those figures, your calculations show the M829A3 as having a penetration value similar to the M829A2. Very troubling given all the time & money spent developing what is suppose to be a superior round.
jaro Posted September 20, 2005 Posted September 20, 2005 Isnt possible that M829A3 dont loose 50m/s/km but 40 or 30m/s/km?
EchoFiveMike Posted September 20, 2005 Posted September 20, 2005 Gents, I'm fairly certain, as certain as I could be without pulling out the micrometer/dial calipers that the penetrator is larger in diameter than 22mm. 25mm seemed accurate. Could all the propellant upgrade have been towards moving a heavier projectile at similar velocities? The advantage of the heavier projecile being better performance vs ERA and complex armour, stuff which simply doesn't show well when talking about simple RHA penetration. S/F....Ken M
John Gillman Posted September 20, 2005 Posted September 20, 2005 Gents, I'm fairly certain, as certain as I could be without pulling out the micrometer/dial calipers that the penetrator is larger in diameter than 22mm. 25mm seemed accurate. Could all the propellant upgrade have been towards moving a heavier projectile at similar velocities? The advantage of the heavier projecile being better performance vs ERA and complex armour, stuff which simply doesn't show well when talking about simple RHA penetration. S/F....Ken M224742[/snapback]--------------------------------------Yes, a shot designer, however, would describe the design effect as increased penetrator "robustness".
jwduquette1 Posted September 20, 2005 Posted September 20, 2005 If we are looking at a 21mm Rod Diameter than we are most likely looking at an in-flight weight of about 13.6-lbs. However if the rod diameter is more on the order of 25mm than the in-flight weight could easily be in the 15-lbs range -- the vast majority of this weight being the DU rod. Assuming M829A3 has similar drag characteristics to M829A2 (i.e. fin drag and body drag are proportional), than our ballistic coefficients for M829A3 would range between 11.8 and 12.5 lb/in^2 for windshield diameters of 27mm & 25mm respectively. While these are both somewhat improved over the ballistic coefficient of M829A2 (a function of the increased weight while maintaining a similar sectional area as M829A2), they are too low to push the velocity drop down to levels of only 30 to 40m/s/Km. Best RegardsJD
jwduquette1 Posted September 20, 2005 Posted September 20, 2005 Most "reliable" sources give a penetration a value for the M829A1 at anywhere between 600-650mm@2000m & a penetration a value for the M829A2 at anywhere between 700-750mm@2000m. Based on those figures, your calculations show the M829A3 as having a penetration value similar to the M829A2. Very troubling given all the time & money spent developing what is suppose to be a superior round.224626[/snapback] Hello pfcem: What are these most reliable sources? RegardsJD
Paul Lakowski Posted September 20, 2005 Posted September 20, 2005 Your post is the 1st I have ever heard of a possible M829A4. Do your calculations take into account that the M829A3 is undoubtably made of a material superior to that of the M829A2? Could you provide your latest calculations for the M829A1 & M829A2?How about the calculation for the British, German, French & other rounds as well? Most "reliable" sources give a penetration a value for the M829A1 at anywhere between 600-650mm@2000m & a penetration a value for the M829A2 at anywhere between 700-750mm@2000m. Based on those figures, your calculations show the M829A3 as having a penetration value similar to the M829A2. Very troubling given all the time & money spent developing what is suppose to be a superior round.224626[/snapback] I've had to down grade M-829A2 since a Master gunner told me the length is 30" and penetrator is ~ 90% of this length or about 70cm, not the 75-76cm I assumed. …..M829A2: .8" Diameter, 30", 10.85 pound depleted uranium "dart: at 5512 f/s. Operating pressures of the M829 series are between 74K psi and 96K psi depending on the particular variant. Muzzle velocity is within ± 78 m/s (256 f/s) between 0 and 120 degrees F (-18 to 49 degrees C)." Based on the smaller rod estimate the penetration figures would be….32L/d with 0.88 P/L reduction and 1.72 scaling. The revised estimate would be.Muzzle [1670m/s] = 1.1 x 70cm = 77.0cm + 2.2cm = 79cm ± 12cm @ 0° & 41cm ± 6cm @ 60° 1000m [1610m/s ]= 1.04 x 70cm = 72.9cm + 2.2cm = 75cm ± 11cm @ 0° & 39cm ± 6cm @ 60° 2000m [1551m/s] = 0.97 x 70cm = 67.8cm + 2.2cm = 70cm ± 10cm @ 0° & 36cm ± 5cm @ 60° 3000 [1491m/s] = 0.896 x 70cm = 62.7cm + 2.2cm = 65cm ± 10cm @ 0° & 33cm ± 5cm@ 60° 4000m [1432m/s] = 0.81 x 70cm = 57cm + 2.2cm = 59cm ± 9cm @ 0° & 30.7cm ± 4cm@ 60° Now based on the ± 78m/s variablity, the best penetration at 2km could be same as the penetration at ~ 750m or about 74 ± 10cm @0° or ~40 ± 6cm @ 60°?
jwduquette1 Posted September 20, 2005 Posted September 20, 2005 I've had to down grade M-829A2 since a Master gunner told me the length is 30" and penetrator is ~ 90% of this length or about 70cm, not the 75-76cm I assumed. …..M829A2: .8" Diameter, 30", 10.85 pound depleted uranium "dart: at 5512 f/s. Operating pressures of the M829 series are between 74K psi and 96K psi depending on the particular variant. Muzzle velocity is within ± 78 m/s (256 f/s) between 0 and 120 degrees F (-18 to 49 degrees C)." Based on the smaller rod estimate the penetration figures would be….32L/d with 0.88 P/L reduction and 1.72 scaling. The revised estimate would be.Muzzle [1670m/s] = 1.1 x 70cm = 77.0cm + 2.2cm = 79cm ± 12cm @ 0° & 41cm ± 6cm @ 60° 1000m [1610m/s ]= 1.04 x 70cm = 72.9cm + 2.2cm = 75cm ± 11cm @ 0° & 39cm ± 6cm @ 60° 2000m [1551m/s] = 0.97 x 70cm = 67.8cm + 2.2cm = 70cm ± 10cm @ 0° & 36cm ± 5cm @ 60° 3000 [1491m/s] = 0.896 x 70cm = 62.7cm + 2.2cm = 65cm ± 10cm @ 0° & 33cm ± 5cm@ 60° 4000m [1432m/s] = 0.81 x 70cm = 57cm + 2.2cm = 59cm ± 9cm @ 0° & 30.7cm ± 4cm@ 60° Now based on the ± 78m/s variablity, the best penetration at 2km could be same as the penetration at ~ 750m or about 74 ± 10cm @0° or ~40 ± 6cm @ 60°?224824[/snapback] This makes a little more sense. However, the inflight weights of M829A1 and M829A2 are practically the same -- A2 is heavier by only 0.35-lbs. I assumed there would be little change in rod length between the two. Moreover, the inflight projectile lengths are basically identical -- 780mm vs 782mm. To me it looks like the rods are the same length, and the only improvements of A2 over A1 were a slight reduction in ballistic drag for the A2, and a substantial boost in muzzle velocity for A2 (+105m/s over Mv for the A1).
jwduquette1 Posted September 20, 2005 Posted September 20, 2005 There have been a couple of articles published over the last few years discussing relative improvements in armor penetration characteristics of successive generations APFSDS. A recent article in Military Parade indicates the improvements have been fairly linear over the last few years. In other words, sudden, huge leaps in APFSDS penetration dont seem to be occuring, rather there has been a steady increase in capability. Running through my own clacs for the transitions in perforation ability M829, A1, A2 & A3 I get something that looks like the attached figure. Of course, like Paul’s figures, these are simply estimates. There are a lot of unknowns and certainly room for debate or doubt.
Guest pfcem Posted September 20, 2005 Posted September 20, 2005 There has to be something missing in these calculations. I find it impossible to believe that after 10 years of developement that the US would produce a new APFSDS round with no significant increase in penetration capability over the previous round (as your latest calculations suggest). It took less than 5 years of developement (based on dates of introduction) for the M829A2 to produce a 15-20% increase in penetration capabilities over the M829A1 (appearantly through the use of a similar penetrator but with a 100m/s increase in mv). All of the pics I have seen show the M829A2 penetrator to be similar to the M829A1 penetrator. The M829A3 penetrator on the other hand is obviously longer & appears to be of a larger diameter as well. M829A1 M829A3 My guess is that the M829A3 penetrator is at least 1kg (possibly even 2kg or more) heavier than the M829A2 penetrator & the 1555m/s mv is either intended to provide the best possible accuracy or purposely misleading.
DKTanker Posted September 20, 2005 Posted September 20, 2005 Hello DkTanker: Thanks for confirming. Frankly I thought attendance at this corner of TankNet was rather limited. I figured if I asked the question, it would go unanswered, and the only source I could lay hands on at that moment was Janes. Regarding Silver Bullet – what about the Lone Ranger? Or the projectile required for dispatching Werewolves (or is it vampires?). Coors Light was just a reflection of my beercentricity. I suppose I should be ashamed of the fact that I actually like Coors Light -- but I'm not. I do have an additional question (perhaps a goofy question), but do recall ever seeing M829 or M829A1 ricochet off of an Iraqi tank? Same question for 120mm HEAT? Best RegardsJD223964[/snapback] Werewolves? Lone Ranger? Got to remember we're talking about GIs, many of whom have rather unpleasant memories of acquiring the need for a 'silver bullet', present company not included. Let me rephrase that. They may have had pleasant memories of acquiring the need, most did not have pleasant memories when they realized they needed the bullet. I don't recall seeing any richochets by APFSDS or HEAT. I'm not saying they couldn't have happened, tracers have been known to become dislogded, I just didn't see any. The only HEAT I know that was fired was fired by my crew and it definitley did not richochet.
DKTanker Posted September 20, 2005 Posted September 20, 2005 There has to be something missing in these calculations. I find it impossible to believe that after 10 years of developement that the US would produce a new APFSDS round with no significant increase in penetration capability over the previous round (as your latest calculations suggest). It took less than 5 years of developement (based on dates of introduction) for the M829A2 to produce a 15-20% increase in penetration capabilities over the M829A1 (appearantly through the use of a similar penetrator but with a 100m/s increase in mv). All of the pics I have seen show the M829A2 penetrator to be similar to the M829A1 penetrator. The M829A3 penetrator on the other hand is obviously longer & appears to be of a larger diameter as well. My guess is that the M829A3 penetrator is at least 1kg (possibly even 2kg or more) heavier than the M829A2 penetrator & the 1555m/s mv is either intended to provide the best possible accuracy or purposely misleading.224894[/snapback] I think you have to take those pictures with a grain of salt, they may be what is purposely misleading. As for the MV, there is no reason to mislead about it, when fielded there are a number of ways to deterime MV through open sources. One can merely look at the firing tables, which are not classified. Getting your hands on one might not be easy, but they aren't classified.
Guest pfcem Posted September 20, 2005 Posted September 20, 2005 (edited) I think you have to take those pictures with a grain of salt, they may be what is purposely misleading. As for the MV, there is no reason to mislead about it, when fielded there are a number of ways to deterime MV through open sources. One can merely look at the firing tables, which are not classified. Getting your hands on one might not be easy, but they aren't classified.224963[/snapback] That is part of my point, people are making calculation estimates based dimensions derived from publicly released photos & the publicly released MV but not much else. Have you seen any of these firing tables?Could you post the data for the M829 series & other comparable rounds here?I would very much like to see what the "actual" data looks like rather than all this speculation. It is not that I doubt the validity of the 1555m/s MV figure, but it would not be the 1st time the public has been purposely mislead reguarding "official" data on military hardware. Given the advancements in propellant technology since the introduction of the M829A2, it would only make sence that the M829A3 would have an equivalent propellant charge at least equal to but more likely greater than that of the M829A2. That means that either the 1555m/s figure is incorrect or the M829A3 penetrator is significantly heavier than the M829A2 penetrator (possibly more than we know). It also makes since that if the M829A2 has a 15-20% increase in penetration capability over the M829A1 using a similar penetrator fired at a higher MV, that the M829A3 would have at least a similar increase in penetration capability over the M829A2 given that it has been in development for twice as long the M829A2 was & has an all new & significantly improved penetrator. Anyone familair with firearms knows that a heavier projectile (while fired at a lower MV) has better penetration capabilities than a lighter projectile (even though it is fired at a higher MV). Edited September 20, 2005 by pfcem
DB Posted September 20, 2005 Posted September 20, 2005 It also makes since that if the M829A2 has a 15-20% increase in penetration capability over the M829A1 using a similar penetrator fired at a higher MV, that the M829A3 would have at least a similar increase in penetration capability over the M829A2 given that it has been in development for twice as long the M829A2 was & has an all new & significantly improved penetrator.224992[/snapback]You do understand that the paragraph of yours that I've quoted above contains a completely baseless assumption? You cannot reasonably extrapolate the hypothetical performance improvement of the M829A3 based on the equally hypothetical performance improvement between the M829A1 and M829A2. You would be assuming that the US Army would only field a new round if it exceeded a single performance parameter by a percentage assigned arbitrarily by you as being of paramount significance. A hypothetical counter: the US Army determines, through intelligence means, that a particular threat category exists for which the M829A2 provides only a 50% chance of perforation at expected engagement ranges. A 20mm improvement in penetration might increase the chance of perforating that hypothetical threat from 50% to 90%. (The numbers are made up, but I believe that they're good enough for this example). The decision to field would be based on a requirement that might read "must perforate target X with 90% probability at Range Y", rather than "Must outperform round A by percentage margin B". There are also many reasons why the M829A3 might have taken longer to develop than the M829A2. The most important of these is that the main threat went away. Russia hasn't been selling T-95s, Black Eagles or much of anything in the ubertank category recently. When the threat goes away, the money goes away and development and fielding times increase accordingly. David
DKTanker Posted September 20, 2005 Posted September 20, 2005 That is part of my point, people are making calculation estimates based dimensions derived from publicly released photos & the publicly released MV but not much else. Have you seen any of these firing tables?Could you post the data for the M829 series & other comparable rounds here?I would very much like to see what the "actual" data looks like rather than all this speculation.224992[/snapback] Have I seen them? Yes. I used to own both the FT-105 w/current changes as well as FT-120 w/current changes. Alas, ten years ago when I retired, I didn't think I'd have use for them so I gave them away.
jwduquette1 Posted September 21, 2005 Posted September 21, 2005 Werewolves? Lone Ranger? Got to remember we're talking about GIs, many of whom have rather unpleasant memories of acquiring the need for a 'silver bullet', present company not included. Let me rephrase that. They may have had pleasant memories of acquiring the need, most did not have pleasant memories when they realized they needed the bullet. oophs...my age is showing again. As to the rest -- I wouldn’t know of such things as the wife has severally restricted such cavorting on my part for more years than I care to remember. Yes I'm whipped. I like Coors light, and I'm whipped. I don't recall seeing any richochets by APFSDS or HEAT. I'm not saying they couldn't have happened, tracers have been known to become dislogded, I just didn't see any. The only HEAT I know that was fired was fired by my crew and it definitley did not richochet.224940[/snapback] The reason I ask is – and in true nerd fashion -- I've been looking over various papers on rod penetrator ricochet. If some of the material is to be believed, it would seem likely that the glacis on a T72 can rebound M829 & M829A1 – ‘IF’ -- the Abrams fires at the T72 from a relative shot angle in excess of about 30 degrees, and at a range in excess of 3000m . In other words if the Abrams shot hits the glacis from outside the 30-degrees envelope it would be in excess of the critical ricochet angle for the projectile/glacis combination. At 2000m the envelope widens in the Abrams favor – now the compound angle of the glacis and shot line would exceed the critical ricochet angle for a shot line in excess of about 35degrees. I threw together the attached figure to better represent what the heck I am going on about. The data supporting these papers is based upon ¼ and ½ scale rods ballistic trials combined with finite element modeling and a wee-schmattering of full scale ballistic trials. Personally I find some of this material hard to believe, but there it is. Academia types have to continuously generate new papers and new research to justify their existence. I figured if there were some practical examples of this sort of thing happening – ala yours or others observations on the battlefield – then it might be easier to swallow. Any thoughts or opinions on the subject?
Guest pfcem Posted September 21, 2005 Posted September 21, 2005 You do understand that the paragraph of yours that I've quoted above contains a completely baseless assumption? You cannot reasonably extrapolate the hypothetical performance improvement of the M829A3 based on the equally hypothetical performance improvement between the M829A1 and M829A2. You would be assuming that the US Army would only field a new round if it exceeded a single performance parameter by a percentage assigned arbitrarily by you as being of paramount significance. A hypothetical counter: the US Army determines, through intelligence means, that a particular threat category exists for which the M829A2 provides only a 50% chance of perforation at expected engagement ranges. A 20mm improvement in penetration might increase the chance of perforating that hypothetical threat from 50% to 90%. (The numbers are made up, but I believe that they're good enough for this example). The decision to field would be based on a requirement that might read "must perforate target X with 90% probability at Range Y", rather than "Must outperform round A by percentage margin B". There are also many reasons why the M829A3 might have taken longer to develop than the M829A2. The most important of these is that the main threat went away. Russia hasn't been selling T-95s, Black Eagles or much of anything in the ubertank category recently. When the threat goes away, the money goes away and development and fielding times increase accordingly. David224999[/snapback] It is by no means baseless to assume that 10 years of penetrator & propellant developemnet would not result in an APFSDS round superior to the M829A2 when less that 5 years of developement resulted in an APFSDS round superior to the M829A1. It does not matter why the M829A3 took longer to develope (not knowing when its development actually began, it may have actualy had a deveopment time similar to the M828A2) but that its introduction into service occurs 10+ years later & therefore most likley takes advantage of the developments that occured over that 10+ year span. England, France & Germany have all developed new APFSDS rounds believed to be notably superior to their previous rounds since the introduction of the M829A2, so why can we not assume that the latest US APFSDS round would not also be notably superior to the M829A2? Paul Lakowski's latest calculations posted here for the M829A2 & M829A3 show the M829A3 to be only marginally superior at <2000m & actually inferior at >2000m.
DB Posted September 21, 2005 Posted September 21, 2005 It is by no means baseless to assume that 10 years of penetrator & propellant developemnet would not result in an APFSDS round superior to the M829A2 when less that 5 years of developement resulted in an APFSDS round superior to the M829A1. It does not matter why the M829A3 took longer to develope (not knowing when its development actually began, it may have actualy had a deveopment time similar to the M828A2) but that its introduction into service occurs 10+ years later & therefore most likley takes advantage of the developments that occured over that 10+ year span. England, France & Germany have all developed new APFSDS rounds believed to be notably superior to their previous rounds since the introduction of the M829A2, so why can we not assume that the latest US APFSDS round would not also be notably superior to the M829A2? Paul Lakowski's latest calculations posted here for the M829A2 & M829A3 show the M829A3 to be only marginally superior at <2000m & actually inferior at >2000m.225454[/snapback]I believe that you are still missing the point. Without wanting this to get heated or anything, you're too focussed on the single parameter that you consider the most important. The Germans introduced a new round recently, not because it offered greater penetration than the existing round, but because it could be used in a wider selection of environmental conditions - the propellant did not vary in performance with temperature to the same degree as the older variant. "England" - and that would be "Great Britain" or "The UK" - hasn't developed a new APFSDS round for a number of yearts, and actually cannot afford to produce a new one to replace the existing 120mm rifled barrel round, so your information is not entirely accurate. Note that jwd's latest musing in this thread might suggest a increased lethality for M829A3 over previous generations *without any need for improved penetration under standard conditions*. I will reiterate - you're too focussed on a single, "sexy" performance parameter. David
Guest pfcem Posted September 21, 2005 Posted September 21, 2005 I believe that you are still missing the point. Without wanting this to get heated or anything, you're too focussed on the single parameter that you consider the most important. The Germans introduced a new round recently, not because it offered greater penetration than the existing round, but because it could be used in a wider selection of environmental conditions - the propellant did not vary in performance with temperature to the same degree as the older variant. "England" - and that would be "Great Britain" or "The UK" - hasn't developed a new APFSDS round for a number of yearts, and actually cannot afford to produce a new one to replace the existing 120mm rifled barrel round, so your information is not entirely accurate. Note that jwd's latest musing in this thread might suggest a increased lethality for M829A3 over previous generations *without any need for improved penetration under standard conditions*. I will reiterate - you're too focussed on a single, "sexy" performance parameter. David225469[/snapback] No. I think you are missing my point. Which is that there is something missing in the latest calculations. Again, 10+years of penetrator & propellant development. We are talking about a time frame greater than that between the original M829 & the M829A2 which represents a >25% increase in penetration performance. Yes, I am focusing on penetration capability, that is primary reason for developing a new APFSDS. Otherwise, we would still be producing the M829 & M829A1 - there would be no M829A2 or M829A3. UK 120mm DU Charm-3 L-27 APFSDS (1998)UK 120mm L-28 APFSDS (200x) [sorry, I was unable to find any specific info on this round other than it being mentioned in a few places] Yes the DM63 was developed to improve the inconsistancy problems that were found with the DM53 but I am unaware of the M829A2 having similar problems & if it were, a replacement would have likely been fielded long ago (most likely prior to 2000).
jwduquette1 Posted September 21, 2005 Posted September 21, 2005 Hi Pfcem: Again, these are just estimates. They are based upon known trends in armor penetration by heavy alloy rod penetrators. Only time will tell how accurate these estimates turn out to be. Moreover as additional information on the M829 series becomes declassified than maybe we will be able to say definately “these were good estimates”, or “these were bad estimates”. But for the sake of discussion, what sort of penetration capabilities do you think would be reasonable for M829A1 through A3. I would be interested to see your take on either Perforation vs. Range or Perforation vs. Remaining Velocity for these three projectiles. Best RegardsJeff
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