Keep in mind that a 7.62mm bullet ( MK18 ) goes through a certain amount of steel or aluminum. Rubber is not as tough as steel, therefor a bullet that can go through say, one inch of steel can go through more than an inch of rubber.
https://en.wikipedia.org/wiki/Anti-tank_rifle
There are weapons, and bullets for said weapons, meant to kill tanks.
Tanks.
Your statement has no base to stand on.