What is the difference between modern artillery and a tank

Modern artillery pieces look alot like tanks, they are vehicles on tracks that have a large 90mm+ cannon on a turrent and a machine gun or two on them. What seperates the two of them? What is the tank good for that the artillery isn’t and visa verca. Is the tank more mobile and better armored while the artillery has a longer range, but even that doesn’t sound like a huge difference between the two.

Hopefully, ExTank will be along in a bit to fill in the details, but if you’ll notice the big difference between the two of them is that the artillery piece you linked do, doesn’t have a rotatable turrent, unlike the tank, which does. There’s more, but I can’t think of them off the top of my head, so I’ll let someone who has a clue provide the rest.

Sorry if I’m saying something obvious, but modern artillery is still designed to fire indirect fire, typically at a greater distance (fire that arcs and plunges). Generally with a longer and wider barrel, etc. Tanks are still designed to use penetrating direct fire. Artillery is set up and fired from a stable position (typically); tanks are capable of firing on the move.

Exactly.

Not so long ago the early versions of the American M-1 had a 105mm gun. Artillery pieces were also 105mm, so what is the difference?

The tank gun is something like a sniper rifle. It fires a very fast solid bullet as straight as it can. The howitzer fires an explosive-filled shell on a higher, longer ballistic loop-the-loop. The tank in a line-of-sight weapon. the artillery operates beyond visual range.

Then the vehicles are as different as night and day. The tank is covered with very strong and very expensive armor plate. The self-propelled gun has slabs of lower-quality metal. The tank is safe from anything but a special anti-tank round. The SP gun is proof against splinters from artillery shells only. Even a rifle round could go though at close range.

The tank has an engine and transmission designed to heave nearly 100 tons around the battlefield like a jack rabbit with fire on his tail. The SP gun moves more slowly with dignity.

Finally, consider the optics. The tank is designed to see at night, through fog and at long distances. It is a hunter-killer. The SP gun uses pretty neat optics and GPS to locate its position and then relies on someone else to tell it where to shoot.

I hope I am not denigrating the artillery. It is a neato piece of equipment. It just lacks speed, armor and optics because it does not need them.

Artillery is a great tool against stationary targets and known target areas. Artillery pieces themselves are not especially heavily armored in comparison to tanks but can offer some defense against direct attack. Still, they aren’t designed to slug it out at close range. They’re designed to stand back but still be mobile. And they’re designed to lob in a lot of munitions as fast as possible.

Artillery is good for counter-battery fire - knocking out the other guys artillery.

Tanks are designed for battles of movement (not for street to street fighting in Baghdad but what is?). They are designed to punch through defensive positions (and other tanks) and then exploit the confusion this causes. Good tank designs have a good combination of protection (armor thickness, tank design, armor type), speed, and offensive punch. Countries that have opted for one attribute over the others have usually been disappointed with the results. Mobile artillery pieces do not have this good combination (lots of punch, less speed, less protection).

So, with the Abrams tank you might have it approaching enemy positions at 40 mph and firing accurately at targets a mile or two away. The crew is looking for enemy tanks and anti-tank weaponry. Its armor design gives the crew the equivilant of about 40 inches of steel protection in the important areas. And it works with groups of other tanks. The enemy scatters when this happens (or has to date) but doctrine usually calls for scattered elements to regroup.

Regrouped enemy = perfect target for mobile artillery.

Surviving elements wandering around = perfect for tanks.

Turns out the M1’s armor is relatively weak on the sides and back: Tanks take a beating in Iraq.

Apparently well placed RPG’s or roadside bombs will get them.

The Army is working on a fix: Tank Urban Survival Kit (TUSK)

Tanks use what is called “fixed ammunition.” That is, the ammunition is like a big rifle round with a brass case to contain the propellant and a projectile of some kind.

Cannons except for the small sizes like 37 mm or 75 mm, ordinarily use a projectile and bagged ammunition. This allows the propellant charge to be varied over quite a wide range of power. That variation of the amount of propellant and the elevation angle of the barrel gives cannons (artillery) a lot of flexibility. For example artillery can hit a target behind some hills by using a relatively high elevation angle and the correct amount of power for the range. Such a target is safe from a tanks gun unless the tank gets on the same side of the hill as the target.

For most effective use artillery needs a forward observer to correct aiming errors.

That’s been the case with tanks since Erwin Rommel was just earning his first star; it’s not unique to the M-1.

Sure, I just wanted to clarify Paul’s ‘covered with very expensive armor’ remark.

US tanks no longer use cased ammunition, but have switched to “caseless” ammunition in which the propellant is combined with a binder and fixed to the shell without the use of a brass casing. I don’t know if any other militaries are using that as well.

Not exactly caseless. It uses a cellulose cartridge which burns off during firing leaving only the aft-cap (a metal disc resembling an ashtray which containd the primer). Some National Guard units still have M1s with 105mm guns. The 105 uses a metal cased ammo.

True, but the propellant charge is fixed and not variable as in bagged ammunition.

Oh and the casing for a 105 tank round is not brass, it’s aluminium. The cellulose casing on 120mm round is blueish grey and feels like hard plastic.