75mm German, US and composite AP shots and shells

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Richard Anderson
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Re: 2 Pdr A.P. Shot v. A.P. Shell

#16

Post by Richard Anderson » 22 Feb 2016, 23:36

Juha Tompuri wrote:Thanks,

So, the M61 at the "Cairo test" was of a similar design as the "hybrid" K.Gr.rot.Pz shell, but with lesser after armour effects, because of being fired as a non-HE shot?

Regards, Juha
It is unclear to me why it would be unfilled.
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Re: 2 Pdr A.P. Shot v. A.P. Shell

#17

Post by Juha Tompuri » 23 Feb 2016, 00:15

Richard Anderson wrote:It is unclear to me why it would be unfilled.
Juha earlier wrote:At the a little blurry text at Cairo test report it is mentioned that the M61 was fired "less bursting charge".
Did I decipher the text correctly?
If so, does less mean here without or lesser?

http://www.panzer-war.com/page43.html
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Re: 2 Pdr A.P. Shot v. A.P. Shell

#18

Post by Richard Anderson » 23 Feb 2016, 14:42

Juha Tompuri wrote: Did I decipher the text correctly?
If so, does less mean here without or lesser?
Yes you did. In this context "less" means "without". I was simply remarking I have no idea why they would do such a thing, since it would require them to unfill a high-explosive shell, which can be a tricky operation prone to sudden "bangs" and much lamentation. :lol: What was the point? What would they achieve in a test that was important? What the M61 would do if the fuze didn't function? But that would be inaccurate, because the dynamics of the projectiles performance would be changed by the change in weight?
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Re: 2 Pdr A.P. Shot v. A.P. Shell

#19

Post by David W » 23 Feb 2016, 21:24

"Terminal Ballistics" Didn't yield anything, what did you think that I might find?

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Re: 2 Pdr A.P. Shot v. A.P. Shell

#20

Post by Richard Anderson » 23 Feb 2016, 21:49

David W wrote:"Terminal Ballistics" Didn't yield anything, what did you think that I might find?
Sorry, I should have looked, I forgot they only tested Standardized materiel and by that time M72 was Substitute Standard. I know there are many different docs from BLR and APG floating about...at least one for M72 AP-T should be available. I'll see what I can dig out.
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Re: 2 Pdr A.P. Shot v. A.P. Shell

#21

Post by David W » 23 Feb 2016, 21:53

Thanks Richard.

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Re: 2 Pdr A.P. Shot v. A.P. Shell

#22

Post by Juha Tompuri » 23 Feb 2016, 23:01

Richard Anderson wrote: I was simply remarking I have no idea why they would do such a thing, since it would require them to unfill a high-explosive shell, which can be a tricky operation prone to sudden "bangs" and much lamentation. :lol: What was the point? What would they achieve in a test that was important? What the M61 would do if the fuze didn't function? But that would be inaccurate, because the dynamics of the projectiles performance would be changed by the change in weight?
Well, perhaps it was the British interest towards the solid block kinetic energy penetrators, and their belief at it's after armour effects. The "Cairo test" revealed the reality (known to many beforehand), but strangely seems that nothing was learned, when writing the report posted here earlier:
ClintHardware wrote: following from WO 195/4639
http://forum.axishistory.com/viewtopic. ... 3#p1997896

Regards, Juha

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Re: 2 Pdr A.P. Shot v. A.P. Shell

#23

Post by peeved » 24 Feb 2016, 12:00

Richard Anderson wrote:
Juha Tompuri wrote: Did I decipher the text correctly?
If so, does less mean here without or lesser?
Yes you did. In this context "less" means "without". I was simply remarking I have no idea why they would do such a thing, since it would require them to unfill a high-explosive shell, which can be a tricky operation prone to sudden "bangs" and much lamentation. :lol: What was the point? What would they achieve in a test that was important? What the M61 would do if the fuze didn't function? But that would be inaccurate, because the dynamics of the projectiles performance would be changed by the change in weight?
An empty burster cavity M61 AP shot appears to have been a factory product: cf. page below from TM 9-1901, Artillery Ammunition, 1944-06-29. Maybe related to the known teething troubles Americans had with AP shell base fuzes causing premature bursts before penetration.

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Re: 2 Pdr A.P. Shot v. A.P. Shell

#24

Post by Richard Anderson » 24 Feb 2016, 14:04

peeved wrote:An empty burster cavity M61 AP shot appears to have been a factory product: cf. page below from TM 9-1901, Artillery Ammunition, 1944-06-29. Maybe related to the known teething troubles Americans had with AP shell base fuzes causing premature bursts before penetration.

Markus
Ah! Of course, that makes sense. Thanks Markus.
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Re: 2 Pdr A.P. Shot v. A.P. Shell

#25

Post by Dili » 24 Feb 2016, 16:51

Just a small note from that pdf that spare tracks expediency as external armor seems it can be effective against those AP rounds.

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Re: 2 Pdr A.P. Shot v. A.P. Shell

#26

Post by peeved » 27 Feb 2016, 18:24

David W wrote:I know that it is a bit arbitrary, but do you know of any penetration figures that illustrate the difference between AP M72 & APC M61?
Some M72 AP shot data below from TM 9-1901, Artillery Ammunition; At 1000 yd a bit better penetration against homogeneous, considerably worse against face-hardened armour than M61 APCBC shot last page (same penetration figures also given for M61 and M61A1 APCBC shells)

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Re: 2 Pdr A.P. Shot v. A.P. Shell

#27

Post by David W » 27 Feb 2016, 18:28

Thanks.

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Re: 2 Pdr A.P. Shot v. A.P. Shell

#28

Post by Juha Tompuri » 27 Feb 2016, 21:58

Urmel wrote:Ah okay. That would explain the lacklustre AP performance I guess.
I guess that "lacklustre" shell being one of (if not the) the best tank anti-tank shot/shell the British had at that moment.

Regards, Juha
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Re: 2 Pdr A.P. Shot v. A.P. Shell

#29

Post by peeved » 27 Feb 2016, 22:32

Re: M61 and M72, in War Office tests by way of http://www.matrixgames.com/forums/tm.asp?m=3016709 the latter apparently had slightly worse performance against homogeneous armour also:
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Re: 2 Pdr A.P. Shot v. A.P. Shell

#30

Post by David W » 28 Feb 2016, 09:36

Thanks for the above, but lots of questions....
1. From what date were 6pdr MkIV & MkV available?
2. From what date was APC available for the 6Pdr MkII & MkIII?
3. From what date was APCBC available for the 6Pdr MkII & MkIII?
4. From what date was APC available for the 6Pdr MkIV & MkV?
5. From what date was APCBC available for the 6Pdr MkIV & MkV?
6. I wonder why no M3 AP Vs FH @ 30 degrees?

Kind Regards,
David.

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