Interlinked Posted May 26, 2020 Share Posted May 26, 2020 Apogee? They mean the maximum height of the projectile along its trajectory. AKA the maximum point blank range or maximum direct shot range. So the effective range seems to be based on the round's maximum point blank range on a generic MBT target. Link to comment Share on other sites More sharing options...
DB Posted May 27, 2020 Share Posted May 27, 2020 "apogee" is appropriate - unless the round is being fired elsewhere than on the earth. I guess that 2.3m is selected as a reasonable "generic MBT" height, as you seem to be suggesting. Link to comment Share on other sites More sharing options...
Przezdzieblo Posted May 29, 2020 Share Posted May 29, 2020 (edited) 125 3BM22, 105 mm M111 and 105 mm NP105A2. https://ibb.co/3mJtbYz Btw. How to paste picture into my post this time without attaching it (which has so low limit)? P.S. "You are not allowed to use that image extension on this community". Mozilla. Maybe I`ll try chrome then. Edited May 29, 2020 by Przezdzieblo Link to comment Share on other sites More sharing options...
JWB Posted May 29, 2020 Share Posted May 29, 2020 Right click copy image. Left click paste image. On chrome anyway. Link to comment Share on other sites More sharing options...
Wiedzmin Posted May 29, 2020 Share Posted May 29, 2020 great pic, with 3BM22 554-562mm long NP105A2 a bit shorter, interesting what was the real penetration of NP105A2 Link to comment Share on other sites More sharing options...
Nikolas93TS Posted May 30, 2020 Share Posted May 30, 2020 Does anybody has information on Dutch trials held in 1979 between US M-735, British L64 and German/Israeli M-111, apparently resulting in adoption of British 105mm APFSDS ammunition. Has that deal went through? Dutch did use APFSDS, but I have no idea on type. Some sources have even mentioned German DM-23 and even DM-33. It seems they have also used British L52 APDS prior to that. Link to comment Share on other sites More sharing options...
Wiedzmin Posted May 30, 2020 Share Posted May 30, 2020 about L64 There is an embarrassment in that the muzzle velocity which was quoted at the Bourges trials which demonstrated the superiority of L64 over the US M735 round, and which was subsequently requited in documents, is not now likely to be met. Although we remain confident of the superior performance of L64 the extent to which this point will of itself incline potential buyers, such as Belgians and possibly even the Dutch, to other solutions remains to be seen. 2. Shatter. Further trials of the basic WNC propellant had confirmed evidence of shatter at low temperatures. This was unacceptable to the UK. MGO asked whether we were being stupid as the propellant was used in the FRG 120mm KE round.S/GR2 RADHE said that the OB would not accept the situation. DGW(A) said that we knew that the Germans were having more accuracy problems and shatter could have something to do with that. In some batches the pressure at -40C was higher than it should have been. S/GR2 RARDE said that this propensity to shatter could not be «blended» out. Tests with reduced diameter granules had not improved the situation. 3. MV. Each batch of basic WNC propellant had shown a different temperature coefficient(the original was about 4 but the latest had reached 5.8). As a result RARDE had been forced to specify an MV of 1472m/sec. Competitive rounds were set at about 1465 m/sec whereas we had predicted 1505m/sec from the UK propellant at the IEPG competitive trials. It might be possible to blend out the temperature coefficient variation but that would not solve the shatter problem. 13. It is unlikely that, even if a successful development programme could be carried out in the time stated above, the MV will exceed 1470 m/s. This will give little edge over the Israeli M111 round, the only advantage of L64 being its greater shot development potential (W/Ni/Fe core, reduced drag). However, the ROFs have as yet given no indication that they are seeking to pursue the potential offer by W/Ni/Fe cores. Conclusions 15. The L64 programme has run into serious trouble in the final stages of its development. A difficult decision must be made within a month as to whether it is wise, or indeed possible, to inject further effort to save the project in view of the scarce resources available at RARDE, PERME and DPEE. THE ROF/SALES DILEMA 8. L64 development is already late. Performance has fallen below that demonstrated at Bourges in 1978 when 1505 m/s mv was announced. (Difficulties with temperature correction for chamber pressure have led to the 1471 m/s figure). Competition from the Israeli M111 round now being manufactured by Diehl in Germany is intense, this round being available in production quantities at very competitive price. RARDE and ROF Birtley are confident that the cause of the core failure has now been identified. The previously planned investigation has now been completed and has cleared both the quality of the components and the overall strength of design, and had shown that the assembly of the projectile to the filled cartridge case is the critical factor. The core failure is considered to have been caused by compaction and assymetry of propellant caused by shouting up using unapproved methods Technically the remedy is simple and there is sufficient time in the programme, due to other slippages, to overcome the problem and prove confidence in the solution. The three tonne of Lot 727 was handsorted to remove short granule length propellant, but this was not possible with the 19 tonne lot as there was insufficient labour available…. i can try find full report on PC, but L64 IIRC never get to any serial use in Europe. as for Dutch army i think they using DM33 https://upload.wikimedia.org/wikipedia/commons/f/f4/120mm_Fin_Stabilised_Discarding_Sabot_-_Tracer_FSDS-T_%28left%29_%26_105mm_Armour_Piercing_Fin_Stabilised_Discarding_Sabot_-_Tracer_APFSDS-T.JPG but it's only museum... maybe somebody have photos of rounds inside tanks ? Link to comment Share on other sites More sharing options...
Przezdzieblo Posted May 30, 2020 Share Posted May 30, 2020 NP105A2 projectile seems to be about 540 mm long, thus core circa 440-450 mm long, circa 25-25,5 mm diameter, 17,6 g/cm3 density of 3,7 kg W-Ni-Fe core.Well... tried arrow's calculator. "Propelling" that rod to 1485 m/s vs 60-degree target 235 BHN gave 460 mm perforation. Assumed quite high velocity drop after 1000 m - 70 m/s. Performance at 2000 m - a bit more than 400 mm. 300 mm still possible between 5500-6000 m. So information about holing 150 mm plate at obliquity of 60 degrees at 5800 m sound plausible. Performance vs NATO single heavy would be lower, because some extra penetration for behind armour effect is needed. British H6/H62, which looks a bit longer than NP105A2 and was fired at tiny higher velocity, could defeat NATO single heavy at 5000 m. Link to comment Share on other sites More sharing options...
Wiedzmin Posted June 8, 2020 Share Posted June 8, 2020 (edited) indian 120mm Edited June 8, 2020 by Wiedzmin Link to comment Share on other sites More sharing options...
RETAC21 Posted June 8, 2020 Share Posted June 8, 2020 I am an ignorant on these matters, but an effective range of only 2000 meters is rather unimpressive, isn't it? Link to comment Share on other sites More sharing options...
GARGEAN Posted June 8, 2020 Share Posted June 8, 2020 "Effective range" for those types of rounds is not something set in stone, like with missiles or arty rounds. It is a combination of factors like mechanical dispersion of specific round from specific cannon, velocity drop and FCS solution, plus different evaluation methods in different countries (like 50% hit chance on tank sized target or 80% chance)So that 2000m is not concrete number and one can surely expect to hit targets at much greater ranges. Link to comment Share on other sites More sharing options...
Ssnake Posted June 8, 2020 Share Posted June 8, 2020 Often enough it's a code word for the tracer burnout range. Or, the tracer burn duration is tailored to match the expected upper engagement range limit, to put some causality into the statement. Link to comment Share on other sites More sharing options...
Echo501 Posted June 13, 2020 Share Posted June 13, 2020 Hello, The QF 20 pdr tank gun was developed in 1948. What was the name and dates of introduction for the various ammo it used? I have the following Mk1 APDS 1947Mk3 APDS 1950Mk4 APDS 1955 unknown APCBC roundunknown HE roundunknown canister round Does this look right? Thank in advance.---Kenny Link to comment Share on other sites More sharing options...
Sovngard Posted June 13, 2020 Share Posted June 13, 2020 Mk4 APDS 1955DS Mk. 4 unknown APCBC roundShot Mk. 1 unknown HE roundHE Mk. 1 Link to comment Share on other sites More sharing options...
Interlinked Posted June 13, 2020 Share Posted June 13, 2020 How common were APDS rounds relative to APCBC rounds? Link to comment Share on other sites More sharing options...
DogDodger Posted June 13, 2020 Share Posted June 13, 2020 Sovngard, what book is that? Thanks! Link to comment Share on other sites More sharing options...
Przezdzieblo Posted June 13, 2020 Share Posted June 13, 2020 Nice illustration. Note difference between APDS no.1&2 and 5&6. No.1&2 are Canadian design, with tappered projectile in pot sabot. No.5&6 are British design, with short cup and 3 petals. Link to comment Share on other sites More sharing options...
Stuart Galbraith Posted June 14, 2020 Share Posted June 14, 2020 The primary colours make me think it was from Barry Beldams canadian armour page, but I dont recall having seen it there. The illustrations at the top look like they come from the Mk3 gunnery manual. Link to comment Share on other sites More sharing options...
Rick Posted June 14, 2020 Share Posted June 14, 2020 From this ex-sailor's memory, but wasn't the NATO 105mm tank gun a modified 20 lber? Link to comment Share on other sites More sharing options...
Stuart Galbraith Posted June 14, 2020 Share Posted June 14, 2020 Yeah, it was the same breech with a new barrel. You could interchange them by screwing on a new barrel, which was quite useful in gunnery training because you could use up 20pdr ammunition in training. Reportedly the Canadians in 1962 had converted all their Centurions over to 105mm. Then the Cuban missile crisis sprang up, and they realised they didnt have much 105mm ammunition, and lots of 20pdr ammunition. So they had to convert all the ones in Germany back again to 20pdr over the space of a weekend. I imagined there was a lot of very unamused troopers at the end of it, particularly when they had to convert them back again... Link to comment Share on other sites More sharing options...
Ssnake Posted June 14, 2020 Share Posted June 14, 2020 ...offset, no doubt, by moderate relief from not having had to go toe to toe with the Russkis in a global thermonuclear war. Link to comment Share on other sites More sharing options...
Nikolas93TS Posted June 14, 2020 Share Posted June 14, 2020 I think most Centurions in Canada kept 20 pounder (Mk.5), while those in Germany were 105mm (M. 5/2, Mk.6 in 1962 and Mk.11 in 1965). I am even guessing that 20 pounders might have outlived 105mm, as Canadian units in Europe switched to leased Leopards in summer of 1977 while the last Centurions in Canada were withdrawn in 1979. Link to comment Share on other sites More sharing options...
RETAC21 Posted June 14, 2020 Share Posted June 14, 2020 I think most Centurions in Canada kept 20 pounder (Mk.5), while those in Germany were 105mm (M. 5/2, Mk.6 in 1962 and Mk.11 in 1965). I am even guessing that 20 pounders might have outlived 105mm, as Canadian units in Europe switched to leased Leopards in summer of 1977 while the last Centurions in Canada were withdrawn in 1979. So it sez here: https://www.canadiansoldiers.com/vehicles/tanks/mainbattletanks.htm It seems upgrading with 105mm guns was done in 1962, so it seems likely only a few were upgraded before reverting to the 20 pounder, By 1971, Canada's Centurions were of the following variants: Mark 5 (20-lbr main armament): 241 in serviceMark 5/2 (L7 105mm main armament): 6 in serviceMark 11 (L7 main armament, uparmouring,infrared sights and lighting, .50 ranging gun): 75Armoured Recovery models: 9 in serviceBridge Laying variants: 4 in service Link to comment Share on other sites More sharing options...
R011 Posted June 14, 2020 Share Posted June 14, 2020 "In service" may be a bit of an exageration. At least by '74, there were only 32 actually running split between two squdrons in Germany and one at CFB Gagetown NB. Link to comment Share on other sites More sharing options...
Nikolas93TS Posted June 14, 2020 Share Posted June 14, 2020 For what was one of the strongest Allied armies in 1945, Canadians certainly held only a token land force in Europe. Link to comment Share on other sites More sharing options...
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