If we kill him that's one... again the goal is to badly wound not kill.
Sometimes. That's essentially the idea behind using a very high velocity but small/light projectile- at a respectable distance, it'll wound to achieve the effect you describe. But should the target choose to engage the shooter from a much closer distance, a hit while the bullet is travelling very fast and at very high rotational speeds will end the dispute quickly.
The alternative view, unfortunately not as convenient for small arms usage as might be desired; XM1028 120mm for M1A1 Abrams smoothbore main gun: