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What the Germans do not need is a small batch of guns using oddball ammo that need either totally new carriages (keep barrel and Breechblock) or large tractors to move.
Leave them in France and use them as AA guns.
Carriage from the pak 38 will certainly not do it in this case.Germans 'converted' 3,712 (?) guns to Pak 1897/38 configuration and often used 5cm Pak 38 carriages to do it.
Pak 1897/38 also use captured French/Polish ammo for the HE rounds and they also used captured Polish AP rounds.
They used German hollow charge rounds in French cases and propelling charges.
There were problems with the Pac 38 carriages, even with the muzzle brake the guns tended to be unstable and the carriages broke more often under repeated firing than the Pak 38s.
See it from the German perspective.Coming up with a conversion scheme for 200 barrels and having to adopt a different carriage and or cartridge to do it?
A lot of effort for not much result.
US had tested the T45, a HVAP for the M3 75mm gun.Perhaps some 850 m/s would've been achievable with the 'cheapo APCR'?
The 75mm SA 44 tank gun using the same ammunition as the AA guns used 1270g of BG5 propellant at 2400 kg/cm² pressure to shoot at 715 m/s, while the 76mm M1 apparently used 1700g (3.75 pounds) of propellant at a chamber pressure of 43k psi or 3000 kg/cm². I suspect that the French were just using more conservative loading for the mle.1928 type barrels and could have got more if they wanted. The case was 518mm long. Another example is the 3" M7 gun using a 1920s/30s barrel which offered the same velocity as the M1 using a greater powder charge (4.87 lbs), reduced pressure (38k psi), and lower proportion of case volume filled with propellant.If you want to start rebuilding something, find something that had a larger base stock to work with.
I have no idea why the French needed a 561mm long case for just 700-715mps velocity. Error? Or using different propellent?
Just to be 100% sure - the report says that 640 m/s is the maximum that can be expected from the gun that is the equivalent of the Mle.97?For the 75 mle.97 pattern, in a document related to development of the fortification assault tanks and their armor, it had been stated "the maximum muzzle velocity achievable in a gun with the interior dimensions of the 75mm mle 97 with a projectile of 6.4 kg (under certain conditions). My interpretation is they meant a gun with the same chamber dimensions (same case), but adapted loading and either the same or a longer barrel much like the 75mm M3 with barely lower velocity, while retaining acceptable barrel life. This 640 m/s gun had been approved for the fortification assault tank before going to the 90mm later on.
What distances are in the question in these examples? When were the tests being made?They got to test a new 75mm capped AP projectile, which perforated a 95mm cemented plate from the Thüringen battleship at 20°, and even 25° for half the shots, at 640m/s (1).
Against a 100mm Schneider naval quality RHA plate, it perforated at 20°, but not at 25° (half-plate deep penetration).
Against 120mm naval quality cemented plate at 0°, it was at the limit of back plate integrity (one spall).
Against 120mm RHA, it only made a 135mm deep dent with a bulge.
75mm mle.1910 couldn't penetrate 100mm plate at all.
Seems like the French 75mm guns were too conservatively loaded, IOW, the propellant charge of under 1300 g for the AA guns. Or, half of the propellant charge weight of what the 7.5cm kwk had on the Pz-IVG and the like.If you want to start rebuilding something, find something that had a larger base stock to work with.
I have no idea why the French needed a 561mm long case for just 700-715mps velocity. Error? Or using different propellent?
There is just too much that needed changing for too few guns. Some sources say they had 6 power scoped available but no AP ammo?
The Soviet guns were already in Russia, they had AP ammo (at least some) they needed few horses or lighter trucks to tow them.
Yes, an equivalent to the mle.97 at least in interior dimensions. Unfortunately the annex which discussed all this didn't say what conditions had to be met for that muzzle velocity.Just to be 100% sure - the report says that 640 m/s is the maximum that can be expected from the gun that is the equivalent of the Mle.97?
What distances are in the question in these examples? When were the tests being made?
Care to elaborate a bit about that gun?
Hi TomoSifting through some web resources, the 'Jaegerplatoon' website gives some interesting data for the Soviet 76mm AA gun firing the Finnish-made APC shot at 20 deg sloped armor (or 70 deg, depending on what side of the pond one is). Supposedly at 1000m it was able to pierce 125mm (almost 50% more than the Pak 40 against the 30 deg sloped plate) - IOW the Tiger I tank is a fair game at that distance. Or, barely worse than the Tiger's gun at the same distance??
J Juha3 - help
I'm still studying armor penetration - trying to understand how much the caliber of the projectile mattered, and how much the design of the projectile mattered for different types of armor and different thickness. Soviets used homogeneous armor of high (or very) hardness, even late cast Soviet armor was high hardness, Germans used heterogeneous armor (with rare exceptions at the end of the war), Americans used medium to low hardness armor with a high proportion of cast parts, etc. In some cases APCR was optimal, somewhere only a high hardness cap was sufficient. In addition to armor properties, the ratio of core size and armor thickness mattered. All this is time-consuming, but I still want to get some kind of overview for myself.These guns were also to shoot the tungsten-cored ammo, again pointing out that their opinion on the steel-cored ammo was very different to yours.
spend some time here, if you haven't alreadyI'm still studying armor penetration - trying to understand how much the caliber of the projectile mattered, and how much the design of the projectile mattered for different types of armor and different thickness.
Thank you! I read the site about 15-20 years ago, probably if I'm not mistaken.spend some time here, if you haven't already
Nathan Okun Naval Gun and Armor Data Resource - NavWeaps
Spalling is the tradeoff for very high hardness armor. one of the reasons why the UK used HESH so muchThank you! I read the site about 15-20 years ago, probably if I'm not mistaken.
Unfortunately now I'm more interested in information that I can hardly find there.
For example, penetration is not necessarily to hit a tank armored with very high hardness armor (i.e. Soviet tanks). It turned out that even just when the projectile impacts the armor a flux of secondary fragments from the inner side of the plate was generated, hitting the crew and equipment in the armored volume.
But the Germans used heterogeneous armor with a medium hardness backside, and the Soviets used medium hardness armor (42SM, 52S) after the war.Spalling is the tradeoff for very high hardness armor. one of the reasons why the UK used HESH so much
Why go to all that trouble when you can just reduce the charge? Just increased powder consumption.A few posts ago in this thread, I've suggested that the small gas divert tube is added to the small AT gun so the recoil is lowered, since part of the high-speed gasses is pushed backwards. That again means that the whole gun can be lighter due to the lower stress exerted on the weapon. Sorta 10% recoiless gun.
Why go to all that trouble when you can just reduce the charge? Just increased powder consumption.