Re: XM25 Individual Air Burst Weapon
XM25 Individual Air Burst Weapon: (Total: 97 Active Cost, 39 Real Cost) Killing Attack - Ranged 3d6, Indirect (Same origin, always fired away from attacker; +1/4), Explosion (+1/2) (79 Active Points); 4 Charges (-1), OAF (-1), Required Hands Two-Handed (-1/2), Real Weapon (-1/4) (Real Cost: 21) plus Penalty Skill Levels: +12 vs. Range Modifier with a single attack (Real Cost: 18)
12 PSLs makes it no penalty out to 256" (512 meters), which is good enough considering the text says 16-600 meters with almost perfect accuracy. Indirect gets it past barriers to explode right above or behind the target hex.
The kill radius of a real grenade is about 5 meters, with casualties ranging out to 15 meters.
So there you go, my take on an XM25 IABW.
Edit: I reread Explosion, and for RKA's it doesn't need the extra radius to do the level of damage I thought. The dropoff is only 1 DC per 1", so using the second option in the book (2 damage per 1" dropoff) should be sufficient. Or you could use 4d6, and make it more lethal out to a "realistic" range.
Edit: On third look, I'd do 3d6 with a -1 DC/2" I think. Grenades are not your friend.