Precision guided DPICM out to 30 km should be plenty.

iirc the longest tank kill from another tank was from [s]a T-80BV callsigned "Bunny" shooting HEAT-FS at a T-80UM2 8 km away[/s] [i]a T-64BV shooting a T-90 with unguided HE-frag from 10.6 km (20 rounds to hit)[/i].