[AlexanderHowl]

In many ways, GURPS fall flat on its face when it comes to realistic portrayals of modern body armor. In general, most modern body armor should probably be semi-ablative against piercing damage while modern ceramic inserts should be ablative against piercing damage (there are metallic inserts that are neither, but they are more recent developments). The result is that modern body armors are good for a few hits from bullets, but they should be replaced after someone is hit by a bullet.

If such realistic changes are implemented though, I would suggest that modern body armor should have its DR doubled without changing cost and weight to account for the fact that you can generally take a few hits without severe injury beyond blunt trauma. With such a change, you will still have players invest in modern body armors even with their potential to suffer declining effectiveness. In addition, a realistic treatment of flexible body armor will halve its DR if stored improperly for prolonged periods, as the fibers will be damaged.