This is an old misconception, and incorrect. All Spitzer-tip (pointed) boat tail bullets are prone to destabilization upon impact with anything hard in their path, deflecting easily off of surfaces (eg. wood, metal, bone). They were not designed to tumble on impact, but to fly straight, fast (high ballistic coefficient).

The same shape (Spitzer-tip boat tail) is used for virtually all modern target and hunting rounds. 5.56 (and .223) is basically a glorified varmint round. Certain 5.56 rounds, however, are designed to be frangible, which causes the bullet to break up on impact and causes more wound channels. Hunting ammo in 5.56/.223 does not do this, as it is designed to stay in one piece.