The thing with armor is that it is designed more to deflect, or spread the impact over a larger area.
With some form of ammunition, that deflection or spreading of impact is minimal. With a club of whatever material, the initial impact area is vastly larger than the impact of a shell.
With some form of ammunition, that deflection or spreading of impact is minimal. With a club of whatever material, the initial impact area is vastly larger than the impact of a shell.