Well I hate to burst your brackets but most low velocity small bore guns on tanks have to bracket the target when they use HESH or smoke rounds.over 1500m, the muzzle velocity is to low for direct fire, ie 533mps or under (At least in the Canadian army anyway).
(ex Cougar commander).
For indirect fire You also use a Gismo called a QFC, Quadrant Fire Control to set the range This is used on the 75mm AT gun mounted on the Scorpion turret to bracket your fire onto your target. Sometimes Ya hit some times Ya miss,
It was used and developed by the British and they had a very similar device use on their guns in WWII. The grandfather of the system used today. But that is just for up and down what about side to side, well most tanks have turret degrees of rotation dial that's used when fireing at night and on preregistered targets of potential enemy routes of advance.
Not accurate but it may just make him think twice about advancing up that route. All modern tank crew rules of ingagement are direct decendents of systems developted in WWI, WWII and Korea.
But what about engagements at 1200-1500m. You use semi-Inderict fire with your gunner sight and bracket your target in two hundred to four hundred meter brackets. Watch for fall of shot and correct. And If your close ie, splashing dirt on the thing, you then go into direct fire mode to take him out. This is where you can use half target corrections and go for the kill. Not fancy, no laser range finder or gyro computer controled guns but a good gunner will hit in 2-3 rounds. And with a good comander who knows how to range estmate a target. usualy 1-2 rounds.
Just an observation, Thanks Harley