What you say about all weapons seems to hold true at times.

I had it where I had one grenade and nothing else early in a game (so better than a crowbar but not as good as being kitted out with guns and everything) but accidentally ran into a building other people were in who were kitted out with reasonable guns. I ran out through an open bit (garage type thing) and was just running away basically going "oh fuck" but I decided to try throwing my grenade anyway and I killed one of them, and managed to get away. I didn't even expect to kill them with it but it must have landed in the right spot. Managed to get away and got to my teammates who weren't that far away and then one of them killed the other person who was in there as well as the one I killed, and we continued on with the game (can't remember how long we survived but longer than that at least).