What happened to the PaK38?

[Raizok]

Originally Posted by Uberhauptstormfuhrer

What i find weird about the pak 38 is that compared with the 6 pounder (57mm) it has only 7mm less, but an equal barrel lenght. However the 6 pounder is 10 times more effective then the pak 38.

Disregarding other, already mentioned factors, you need to keep in mind, that, while the caliber increases, the mass of the projectile increases more than linearly (by how much exactly - I leave that as homework).