QUOTE (WearzManySkins @ May 5 2008, 08:47 PM)

Read and enjoy
Grenade WikiTechnically grenades produce shrapnel.
Technically they produce fragmentation. Only Shrapnel Shells produce shrapnel. And since they haven't been used since about 1915....
However grenade fragments are much easier to stop then bullets and would also be much easier to stop than the common (intuitively obvious) conception of how flechettes work. Sharp, pointy and fairly long objects are actually pretty darn effective at going through flexible body armor.
But my understanding is that flechettes don't actually work in real guns (I'm talking shotgun shells or artillery shells here) the way that is intuitively obvious that they should, if you see how they are packed into a round you'll start to see why. I can't find a good web image, but they are packed in with half the flechettes pointy end aiming forward and half pointing to the rear, to maximize round fill. So many of them will be trying to flip over in flight.
Now for small arms shooting individual flechettes, that is a bit different. A brief history of the biggest sinkhole for money and skilled labor in US small arms history:
The Special Purpose Individual Weapon