Pak 38 Pzgr.40 and 40/1

[Mobius]

Thanks a lot Miles. These are great.

Though either the penetration data of APCR/1 on the OP or that on the Krupp cores graph is correct. There is some difference around 500 - 600m range. (Unfortunately the range I choose to base my APCR ballistics.)

So going by that graph and we assume APCR correctly penetrates 72mm @ 500m it then must strike at 844.5 m/s. So my table and graph in a previous post is slightly off.

[Miles Krogfus]

The Graph I posted is created from the Krupp one. Other pages for your Pzgr.40 information:
page 1 from H.Dv. 119/324 Pak 40 75 mm.
pages 2 and 3 from H.Dv. 119/328 Tiger I 88 mm.
page 4 from H.Dv. 119/329 Pak 43 88 mm. (Unlike page 1 and pages 2-3, I combined two pages from this FT to get them on one page.)

[Mobius]

The two APCR graphs have proved very useful. Though they don't perfectly support each other they have let me narrow down the strike velocity of the APCR bolt. What I get is at 500m the APCR velocity was between 836 to 850 m/s.

[Mobius]

One person asked if any of the collectors, who have been doing this stuff for a long time, and some are EOD guys, if they ever came across an actual 40/1....apparently not. It may have been designed but not implemented especially after 1943. I suppose it may have been possible to refurb the projectiles from the short 5,0 cm KWK for the Pak 38 and KWK 39.

They should of asked someone in the Yugoslavia Army. They apparently had a stock of the 40/1. Enough in the 1950s to test fire them.
Vs. T-34/85 Hull=46mm@60° Turret=90mm rounded (M40/1 is Yugo name for Pzgr. 40/1.)
M40/1 sub-caliber penetrates upper front hull @ 400m.
M40/1 subcaliber penetrates front turret @ 200m.
Vs. M4A3E4 Sherman Hull=64mm@47° Turret=90-94mm curved.
M40/1 sub-caliber penetrates upper front hull @ 500m
M40/1 sub-caliber penetrates front turret @ 250m

It looks like developing the 40/1 was a waste of time. As the advantage of the 40/1 over the 40 appears only after ~375m so would have no noticable affect on these two common opponents.

[Yoozername]

The 40/1 used by the Yugos could have come from the German stockpiles of recalled bolts (made into 40/1 projectiles post WWII), already completed projectiles that were never completed into ammunition, or possibly recalled whole ammunition. The Yugos reconditioned much ammunition from WWII era, basically meaning they replaced propellant and fuzes. The velocities could be different. I am not sure there is much other information regarding these tests besides what has been seen on the web and available on your website.

The 40/1, due to the design having the driving-band further back, may have had more volume for propellant, but then again, it needed more propellant since it had a heavier projectile. One thing that is interesting is that it seems to have a bit more performance against the shermans than T34. But, I agree, the 40/1 while very accurate, did not offer much improvement over the 40.

In any case, the Yugo tests showed many weapons were not viable against the post war armor, and I would expect them to scrap most ammunition for these weapons. I doubt many other countries would be in the market for it. Collectors were not really 'around' at that time, so most are now digging these things up out of the ground on old battlefields.

[Peasant]

Found a much better quality copy of that chart for the 5cm Pzgr.40 shell:



The ballistics here are clearly wrong for an arrowhead APCR shell. Using flight model of the 3.7cm Pzgr.40 I've estimated, approximate terminal velocities for the early 5cm Pzgr.40 shell:



Kruppe penetration curve gives the following performance against 30° plate with these terminal velocities:

• 100m; 122mm
• 200m; 106mm
• 300m; 93mm
• 400m; 82mm
• 500m; 72mm
• 600m; 63mm
• 700m; 55mm
• 800m; 47mm

[Peasant]

H.Dv.119/312 gives the early round the mv = 1050m/s or 3444fps, supporting the "3440fps" figure from british chart.
Meanwhile H.Dv.119/313 gives the long 5cm gun 1180m/s(3871fps) with lighter shell and 1130m/s(3707fps) with heavier shell.

[Peasant]

Penetration of subcaliber shells is influenced very strongly by hardness/tensile strength of the target. For example "Datenblatter fur Heers-WFH" shows the penetration of 7.5cm PzGr.40 at 100m against 80-90kg/mm^2 plate as 126mm/30°. Knowing how conservative germans were in their penetration criteria, I'm wondering whether or not this figure was obtained for the average(85kg/mm^2) or worst case(90kg/mm^2) scenario tested?
Can someone shed light on this?

[Mobius]

Found a much better quality copy of that chart for the 5cm Pzgr.40 shell:

That UK graph is very accurate. It is very close to the German firing data. Unlike the UK graph of the 88mm Pak 43.

[Thoddy]

...You would have to translate it from BASIC to your favorite code.
https://www.tapatalk.com/groups/warship ... 36818.html

As far as i can see, the outer ballistics program based on W. Jurens appears as good.

Except for the part of longer range naval shell flights.
At high angles of elevation drift becomes a considerable source of inaccuracy. Aside from the curvature of earth.....and other long range problems...coriolis, west->east shot vs east->west shot.

[Peasant]

I have a head scratcher for you all:

If the curve labeled D is for 7.5cm PzGr.40 for Pak 40, C is for Kwk 42 and A is for the Tiger I and II subcaliber shell (I've compared the penetration values with ones given in the manuals for respective wepaons), then what kind of shell is B? Is it some kind of 88mm experimental APCR design with a smaller core? But if it's the same core as the one in Kwk 42 APCR, why does it pen so much more?

[Christian Ankerstjerne]

Could it be for the Flak 41? Its numbers were quite similar to the Kw K 43:
https://panzerworld.com/armor-penetrati ... 88-mm-guns

[Peasant]

Could it be for the Flak 41? Its numbers were quite similar to the Kw K 43:
https://panzerworld.com/armor-penetrati ... 88-mm-guns

It's not about the weapon the shell is fired from. The same shell fired at different muzzle velocities will display different relationship between thickness penetrated at given distance, but the relationship between striking velocity and thickness penetrated is the property inherent to the shell itself, not the weapon it's fired from.

The only way this could change its internal design differed.

Or maybe this is just a typographical error in this document and I'm excited over nothing.

[Christian Ankerstjerne]

It's not about the weapon the shell is fired from. The same shell fired at different muzzle velocities will display different relationship between thickness penetrated at given distance, but the relationship between striking velocity and thickness penetrated is the property inherent to the shell itself, not the weapon it's fired from.

The only way this could change its internal design differed.

Or maybe this is just a typographical error in this document and I'm excited over nothing.

I misread your post (I'm well aware about the relationship between guns and projectiles).

A good place to start could be the drawings here, though they are unfortunately not yet digitalized:
https://invenio.bundesarchiv.de/invenio ... 7b969a9f0/

[Thoddy]

Could it be for the Flak 41? Its numbers were quite similar to the Kw K 43:
https://panzerworld.com/armor-penetrati ... 88-mm-guns

Unlikely Pzgr 40(Hk) was only used by Panzer and Panzerjäger.

Flak (Luftwaffe/Kriegsmarine) units had Pzgr 39.