WWII: 40mm Autocannon VS tanks?

[Ulzgoroth]

Originally Posted by Calvin

As a player of Warthunder I can say that the game gives a lot of ammo options. Even with AA vehicles you can select ammo usually designed for AT rather than AA work. In that particular clip the cannons were likely using pure AP or API rounds. I think the game designers are aware that players will use things in ways for which they were never intended.

At least for the US 40mm AA mounts, it looks like the AP rounds were in service with the army, though whether they were actually issued to the vehicles I can't say. Both the M19 and M42 40mm AA vehicles seem to have in practice mainly been used against ground targets, because historically US forces with them never saw much enemy air power. Of course, in reality (unlike War Thunder) ground targets often are not armored vehicles, so they might not have needed the AP for that.

[Tomsdad]

Originally Posted by Tallor

Would an AA gun really use AP ammo, though? Assuming it was loaded up to fight aircraft.

A dedicated AA gun might not (but as noted they did sometimes), but there nothing specifically AA about a 40mm cannon.

The main issues with AA guns is it has to fire fast rounds quickly to cover the long distance from the ground to your aerial target and have a chance of hitting them.

The famous '88' started life as an AA gun, it's just firing a high velocity round with long effective range is good for antitank work as well (if you put a AP etc round on it)

Originally Posted by Tallor

So if I invent parking garages, then drive the AA gun up a parking garage, and fire downwards, I might destroy a WWII tank with WWII AA technology? :P

not quite sure what you mean by 'might'. WW2 tanks were quite happily knocked out by planes with cannon in WW2 without having to be parked in garages?

Imagine a bunch of those German 37mm cannon flying around overhead of Shermans at (Dmg 7dx4(2) pi++). with a 2d [2d] cr ex follow up vs. top deck DR50 and HP 158.

Or even the turret where the crew gets that enclosed 2d [2d] hit which isn't much of a consolation prize after nervously watching the GM roll on the "damage to occupants table" for what's left of the 7dx4(2) pi++ once it got through the DR70 turret roof!


There's a reason why we were rather happy to have air superiority!

[Ulzgoroth]

Originally Posted by Tomsdad

not quite sure what you mean by 'might'. WW2 tanks were being quickly happily knocked out by planes with cannon in WW2 with out having to parked in garages

Imagine a bunch of those German 37mm cannon flying around overhead of Shermans at (Dmg 7dx4(2) pi++). with a 2d [2d] cr ex follow up vs. DR50 HP 158


There's reason why we were rather happy to have air superiority!

Worth noting that the BK 3,7 didn't use APHE rounds. APCR (APHC) was used against tanks, and HE against bombers.

But yeah, planes with cannon killed tanks.


And, to re-iterate, early-war armor had a lot less protection sometimes. I did some work statting the protection of the T-26, for instance. That thing wouldn't stand up for long to an M2HB firing ball rounds, never mind an autocannon throwing AP.

[Tomsdad]

Originally Posted by Ulzgoroth

Worth noting that the BK 3,7 didn't use APHE rounds. APCR (APHC) was used against tanks, and HE against bombers.

True (although since such rounds did exist for similar cannons, i.e. such a thing is possible)

Originally Posted by Ulzgoroth

But yeah, planes with cannon killed tanks.


And, to re-iterate, early-war armor had a lot less protection sometimes. I did some work statting the protection of the T-26, for instance. That thing wouldn't stand up for long to an M2HB firing ball rounds, never mind an autocannon throwing AP.

Very true, and although they were rendered obsolete pretty quickly those great long anti tank rifles weren't there for fun!

[The Colonel]

Originally Posted by Tomsdad

Very true, and although they were rendered obsolete pretty quickly those great long anti tank rifles weren't there for fun!

Admittedly, they weren't much use against tanks either. Rumour has it that the British Army mainly used them as a punishment detail ... although I do recall an account of them being used to break rocks for sangar construction in North Africa.

Originally Posted by Tallor

So if I invent parking garages, then drive the AA gun up a parking garage, and fire downwards, I might destroy a WWII tank with WWII AA technology? :P

Mad Uncle Adolph (or possibly his henchman Albert Speer) sees your parking garages and raises you a flak tower. And not just with 37mm FlAK guns ... they put 12.8cm guns up there. Gave the Russians fits during the invasion of Berlin ... and frankly weren't much fun for the RAF and USAF either.

[Anders]

Originally Posted by Tomsdad

The German's had a 37mm cannon which I think came out of the Flak 18/56 the closest in High tech to that is I think the Rheinmetall 3.7cm PaK, written up in pg 140. (But if anything the other cannon will better with higher muzzle velocity etc).

Isn't that the one they nicknamed "German Army Doorknocker" during Barbarossa, because it was completely ineffective against Soviet medium and heavy tanks?

[Ulzgoroth]

Originally Posted by Anders

Isn't that the one they nicknamed "German Army Doorknocker" during Barbarossa, because it was completely ineffective against Soviet medium and heavy tanks?

The 3.7cm PaK is, yes.

There's a very big difference between shooting at the front or side armor of a tank, and shooting at the top armor. (Also, never bothering with the lower-performing APEX shells would have helped.)

[The Colonel]

Originally Posted by Ulzgoroth

The 3.7cm PaK is, yes.

There's a very big difference between shooting at the front or side armor of a tank, and shooting at the top armor. (Also, never bothering with the lower-performing APEX shells would have helped.)

Also they made that giant rifle grenade for the PAK 36 which apparently could pretty much wreck anything if you could get it to hit.

[Tomsdad]

Originally Posted by Anders

Isn't that the one they nicknamed "German Army Doorknocker" during Barbarossa, because it was completely ineffective against Soviet medium and heavy tanks?

Yep, and if you shoot it at the front of a tank it won't do much good it's true (but it depends on which tank of course)

7dx4 (2) is stopped on average by DR196, and if your just relying on penetration to do damage lower DRs will still stop a lot of the damage.

Originally Posted by Ulzgoroth

The 3.7cm PaK is, yes.

There's a very big difference between shooting at the front or side armor of a tank, and shooting at the top armor. (Also, never bothering with the lower-performing APEX shells would have helped.)

Interesting point about the lower performing APEX, HT has their penetration as the same as the APHC, both at 7dx4 (2) and the follow up on the APEX is a bonus, do we need an errata here you think?

[Anaraxes]

The old Avalon Hill wargame Tobruk (1942, African desert, individual vehicles or infantry squads) included the Bofors 40mm AA gun. It was a fearsome anti-tank weapon in that game because of the rate of fire. The combat system was quite simulationist, obsessed with armor values and round penetration, and had a chart for detailed hit location on a tank (tracks, hull, etc) including a small chance to hit the turret ring between the hull and the turret. This occurred on a 2d6 location roll of 12, so a 1-in-36 chance to hit the turret ring, which would kill just about any tank. And while the Bofors penetration was not remarkable, it did have RoF 40. So odds were if you shot at a tank, you'd kill it.

(And even if not, an M-kill on the tracks was extremely likely.)