Tank HE shells dont one shot with the splash radius and for whatever their shells drop severely. IFV shells bloom to much to accurately shoot at snipers.
While I also occasionally snipe based on my mood (mainly for counter sniping), I also may make my purpose to wreck some sniper somewhere. Because a sniper is someone who invites aggression both in game and in real life warfare.
Please allow me to point out the best vehicle based projectile for striking at snipers: The Aim guided shell/rocket aka ToW. You can lead it all the way to their face.
Also depending on how much you are into countersniping, you can also get to them by using agaist them the SVK DMR because the DMRs have no glint to warn the sniper.
You should also be able to suprise a sniper by using sniper decoys to hide your own glint so that they will not have a star guiding them to your head.
Depending on the distance and the geometry, you could also try to land mortar shells on them. Eventually you they will either perish or get off their roof.
