No Parley Achievement
Get a kill with the old cannon
Load up a game of Conquest on the Operation Mortar map, and work your way up the hill (or fly) to B flag. There are three cannons up there to choose from, two overlook the water, and one overlooking land (E flag). The best one to use is the one that overlooks E flag, as there is a path up the hill, and players will often use it to get to the hilltop where the cannons are.
Hang out near the cannon, and wait until you see an enemy coming your way. When you spot one, hop into the cannon, aim, and blast away. To aim, ignore the white targeting dot, and instead line up your shot with the bottom of the cannon. It'll might take you a few attempts, but is pretty straightforward.
Here's a video by HarryNinetyFour, though it's doubtful you'll get as lucky a kill as he did: