What is the difference between anti-tank guns and self-propelled artillery?

Question

Why can’t I just aim the artillery down or the anti-tank up? Why do they have to be different guns?

In: Engineering

Answer 1

Self Propelled Artillery is generally something like the [M109 Howitzer](https://en.wikipedia.org/wiki/M109_howitzer) where its a gun mounted to a motorized chassis while Anti-Tank guns are generally portable but not self propelled. The main differences between them is how far up and down the gun can go.

In some scenarios they have been exactly the same gun just sporting different ammunition. In WW2 the Germans used the 88 mm guns to great effect in a variety of roles. It began as the 8.8 cm Flak but was later turned into the 8.8 cm KwK and 8.8 cm PaK which were used as the main cannons on Tiger tanks and their heavy tank destroyers. Load a high explosive round and you’ve got yourself artillery, load a time high explosive round and you’ve got an anti-air gun, load an armor piercing round and you’ve got an anti-tank gun

In general though, once mounted onto a self propelled vehicle a gun will only serve a single purpose.

Your self propelled artillery doesn’t need to be well armored since it should be a ways away from the front, it needs to be a stable platform for consistent shots, carry a lot of ammo, and be able to get into position quickly.

Your anti-tank gun is going to be mounted in one of two ways. In a tank destroyer its going to be in a big vehicle mounting lots of armor so it may not be in a full turret which can point up, but it will be able to take a hit. The other option is a gun motor carriage which is a truck with a big gun on it that can shoot and quickly scoot away because it can’t take a hit. You also wouldn’t want a turret that supports a lot of elevation on this because then you’re heavy, slow, and dead.

Military systems generally don’t want one thing that good at everything. It seems handy to consolidate your supply chains but it really messes with the designs and can make everything more expensive. Often the cheapest and fastest solution is to make one thing that good at one thing, and a second thing thats good at a second thing. Making one thing good at two things takes 3x longer and costs 8x as much.