Artillary

Here is the idea: You get a 9 kill streak and a flare (red stone torch) pops up in your inventory kind of like it is in FPSHG. You throw the flare where you want it to go. Then 3 seconds later, a barrage of 8 TNT automatically fall from the sky and kill people in the AO. The tnt will have the AOE and damage just like the grenade has.

Second option:

9 kill streak. Throw the flare and 10 tnt will randomly fall from the sky on the enemy side.

edits: 9 kill streak needed to unlock the barrage.