Go to FC Arcade, Solo/Coop missions, Search and set up Featured. Then you will see 10-12 maps, made by Ubi. Best worked for me, Head hunter map for pistol kills, shotgun kill on Journey map, and 4 times quick Journey, called Lost time or someting like that,
Edit: Terminal with pistol, Upside down - Journey map, done in 2-3 minutes top, Safe Haven - Journey with shotgun.