system
Given the following post, respond as if you're commenting on Reddit:
human
Why are bullets rounded instead of being sharp (like a bullet-arrow)?

We progressed from bow and arrow to guns and bullets, I am just wondering what drove them to be rounded off instead of sharp pointed.
gpt
At the speeds bullets are fired even a round one will easily penetrate human skin. Therefore bullets are shaped to maximise the accuracy of the weapon, minimize drag when they're in the air, and inflict a lot of damage when they do penetrate your body. Some of the deadliest bullets are in fact made with a small pit in their tip in order to cause them to expand upon impact with the target, making the wound much more deadly ( These are known as hollow-point bullets ). 

Now military bullets often do have a "pointy" cone shaped bullet, but this is mostly for aerodynamics ( a streamlined bullet experiences less drag than a round one ). 

If the goal is to penetrate armour, then typically the bullets will consist of some heavy penetrator made from tungsten-carbide or uranium, since these materials have a very high density and also mechanical properties that let them penetrate thicker layers of armour before disintegrating. These materials are also very damaging to the rifle they are fired from, so they almost always have a jacket of a softer metal which is less harsh on the rifle. Upon impact this jacket fractures, and the heavier core proceeds to penetrate the target's armour.