It says get 100 rapid kills with a weapon of the same archtype as the Seasonal Weapon, which is the Grenade Launcher (Cry Mutiny). I'm using the "Cry Mutiny" grenade launcher but it does not count for Free Lance Gambit. It does count for Vanguard Ops Playlist. If Free Lance Gambit is not a playlist (it sure counts for Gambit Bounties), please indicate it because it's absolute TRASH that none of my Kills count on that list. This is absolute BS that you people can't even be bothered to properly document the requirements for what does or does not count as a "PlayList". Very sleazy way to drive up the player hour count.