Anti-tank grenades are your failsafe when ll else fails.
In my experience if they hit they do damage 100% of the time. Not always a hull destroyed, but at least crew injured, usually more.
I run 2-3 infantry at a tank with anti-tank grenades which if they don't get killed enroute almost always ends in a tank dead.

Mid game start stealing wrecked enemy tanks by knocking them out then assigning infantry the wrench command (repair) and send them to a dead enemy tank and repair it. Then grab 3 more men for a 4 man crew and snap! you have a FREE tank.