Great contribution from Cavguy at an SWJ discussion about the XM-25 (see below)...

We really do not (or at least did not as of 2008) train enough with grenades, to include fragmentation hand grenades, stun hand grenades (M84), the M203/M79, or the MK19. It is too bad because these are incredibly useful weapons when you know how and when to employ them and incredibly counterproductive weapons when you do not know how and when to employ them. This is true of most high explosives (AT-4, C-4, det cord, shock tube, etc), but the "safety first" mentality prior to 9/11 resulted in little to no training on these tools/weapons until recently. The institutional knowledge was drained by time and attrition.