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Main Gun Ammo - Revisited


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#1041 Interlinked

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Posted 19 September 2019 - 1318 PM

Small but important announcement: Willi Odermatt has updated his long rod calculator!

 

http://www.longrods.ch/start.html

 

He has added some additional functions into the calculator on his website and he explains some of the nuances between penetrating a semi-infinite homogeneous RHA block vs an RHA plate array (http://www.longrods.ch/semi.php). The new calculator is more useful than ever, although now it no longer calculates the penetration of steel long rods, only their perforation limit.

 

I think everyone will find this very interesting and useful.


Edited by Interlinked, 19 September 2019 - 1339 PM.

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#1042 Wiedzmin

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Posted 23 May 2020 - 0427 AM

sLbsM6I.jpg0UUb27R.jpg

EEq2aHn.png

 

posted by Sovngard

 

H6/62 105 mm APFSDS


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#1043 RETAC21

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Posted 25 May 2020 - 0238 AM

Who uses this round?


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#1044 Wiedzmin

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Posted 25 May 2020 - 0436 AM

nobody AFAIK, but 115mm APFSDS BD36/2 for Egypt was based on this 


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#1045 Sovngard

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Posted 25 May 2020 - 1123 AM

Who uses this round?


In 1987, RO Defence demonstrated a new 105mm APFSDS round (the H6/62) as a replacement for the L64 APFSDS round. The round is compatible with the L7 gun and the French F1 gun. While BAE Systems has not released any details, RO reportedly enjoyed significant sales through the 1990s.

I have read rumours that the H6/62 was used by the Pakistani army.

 

Performance-wise, the H6/62 is comparable to the French OFL 105 G2 and the Israeli M413 Hetz-7 105 mm tungsten APFSDS (both defeat the NATO Heavy Single Target at 6000 m)


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#1046 Przezdzieblo

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Posted 25 May 2020 - 1318 PM

Pakistani P1A1 round looks like L64, not like H6/62.

 

NATO single heavy target is 150 mm at 60 degrees obliquity, thus 300 mm RHA to make it simpler. To defeat that target at 6000 m it would need 400+ mm penetration at 2000 m. According to Janes OFL 105 G2 can defeat NATO single heavy at 7400 m.


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#1047 Sovngard

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Posted 25 May 2020 - 1331 PM

Pakistani P1A1 round looks like L64, not like H6/62.


Thus, the H6/62 has been sold elsewhere.
 
 

NATO single heavy target is 150 mm at 60 degrees obliquity, thus 300 mm RHA to make it simpler. To defeat that target at 6000 m it would need 400+ mm penetration at 2000 m. According to Janes OFL 105 G2 can defeat NATO single heavy at 7400 m.

 

OFL 105 G2 : 6800 m

Spoiler


M413 : over 6000 m


Spoiler


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#1048 Przezdzieblo

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Posted 25 May 2020 - 1417 PM

7400 m mentioned by Tony Williams, click.

 

Well, there is no sense to play around with unverifiable values, lets agree 7000±500 m ;) Standard NATO targets are so obsolete since 80s.


Edited by Przezdzieblo, 25 May 2020 - 1419 PM.

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#1049 KV7

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Posted 25 May 2020 - 1505 PM

No one was ever going to fire it out beyond 3000 meters or so anyway.


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#1050 DB

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Posted 26 May 2020 - 1606 PM

Well, the GIAT data clearly states an effective (combat) range of about 2000m, based on the "apogee" of 2.3m - presumably some sort of standard, so even 3000m is optimistic.

 

The English translation of "distance de perforation" as "depth of perforation" is inaccurate (!)

 

1.38 seconds to 2km is an average of 1449m/s, and so a (linear assumption) velocity drop per km of about 76m/s. Seems plausible.


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#1051 Interlinked

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Posted 26 May 2020 - 1635 PM

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. 


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#1052 DB

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Posted 27 May 2020 - 0654 AM

"apogee" is appropriate - unless the round is being fired elsewhere than on the earth.  :D

 

 

I guess that 2.3m is selected as a reasonable "generic MBT" height, as you seem to be suggesting.


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#1053 Przezdzieblo

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Posted 29 May 2020 - 1506 PM

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 by Przezdzieblo, 29 May 2020 - 1517 PM.

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#1054 JWB

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Posted 29 May 2020 - 1514 PM

Right click copy image. Left click paste image. On chrome anyway.

3bm22m111np105a2.jpg


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#1055 Wiedzmin

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Posted 29 May 2020 - 1546 PM

great pic, with 3BM22 554-562mm long NP105A2 a bit shorter, interesting what was the real penetration of NP105A2


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#1056 Nikolas93TS

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Posted 29 May 2020 - 1926 PM

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.


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#1057 Wiedzmin

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Posted 30 May 2020 - 0312 AM

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.wikim...er_APFSDS-T.JPG

 

but it's only museum... maybe somebody have photos of rounds inside tanks ?


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#1058 Przezdzieblo

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Posted 30 May 2020 - 0543 AM

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.


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