I've never gotten a triple kill with a grenade on this game. I don't think the radius is big enough to finish off 3. But I have gotten several doubles, and it feels good man.
I was messing around a bit ago with TDM on Noshar. Three kept hiding in the same dead end container. With enough people shooting in, my grenade was able to pick up the triple.
I remember getting my Destruction D2.0 kill on GM in one game.
Joined his and Leads game in progress(back when I only played with Lead), it put me on the other team, I saw GM Gustav whoring out a window on Port Valdez Rush. 6 things of C4 later, GM was dead and I had my cheevo.
I think I got a triple kill with a grenade yesterday actually on metro as the russians,was spawn killing the us side on CQ,in that middle locker room place,I threw a random grenade around the corner and boom lol
tried to get that achievement for killing with a carbine(M4),pistol(G18),and rocket launcher(RPG) without dying,and I did,but I guess you actually have to have the DLC for it to work
Best grenade I've got was a 5-piece on grand Bazaar when half the enemy team was guarding B on the 1st base after they armed and I just threw 1 in and got lucky.