Artillery Guns and Howitzers with direct fire

[Marcello]

Originally Posted by Suhiir

With a few (mostly Russian) exceptions artillery isn't used for direct fire work these days so there's rarely much in the way of AT type ammo available for them, perhaps HEAT but rarely AP or SABOT.

Not to say they aren't occasionally used for direct fire at need (say when being overrun) or in unusual instances (I recall they used 8in howitzers vs some bunkers on the Sigfried Line).

I'm not even sure if the US 105mm howitzer can even fire the ammo used by the M60 tank.

It depends. During WW2 it was not unusual to use artillery in the antitank role and there were still plenty of smaller caliber weapons (stuff like 25 Pdr or the Zis-3) that were suitable to deal with at least some of the tanks they faced.
Afterwards tanks got thicker skins and the lighter artillery calibers were dropped for various reasons. Neverthless the soviets kept developing and issuing antitank artillery round for all the new arty pieces until the 70's IIRC. These would be either HEAT or some sort of AP, not sabot as there would be various issues with the latter and probably not worth the investment anyway.
The West stopped earlier, though note that direct fire egagements could still happen: at Osan the american howitzers engaged the north korean T-34s with HEAT in direct mode.