It's sad to say this, but yes. Within the industry body armor is more commonly referred to as a ballistic resistant vest, because unfortunately nothing is 100% bulletproof. That being said, if your armor is equal to the task of the threat you are dealing with you should be fine, provided the round strikes the protected area of the vest.
As we mentioned before, different levels of armor are rated for different threats. Wear armor appropriate to the situation you are going into. If you expect to deal with rifle threats, you should be donning rifle plates. If you are going to a pistol-only shooting range and are only concerned with poor range practices and ricochets, a concealable vest should be fine.