Armor-piercing bullets are very dangerous and should not be available to anyone, even within the military. Having no experience with armor-piercing bullets, I cannot say for certain if they would halt a tank, but I would hope they cannot.
Tanks are built to withstand tremendous impact. If there is a bullet out there that could do damage to a tank, that would be scary. I am not even sure that any gun on the market could facilitate a bullet strong enough to pierce a tank.