At the start of the round, most players will be capping there starting flag (A or C). This means you know EXACTLY where they are.
line your cursor up with the A or C letter, look upwards and let some axes fly.
Repeat the process over and over and eventually you will get it right.
This is the way I did it, I hope it is of some help to you.
I would reccomend carrying 2 yes. throwing them both will increase your chances by 2.
it took me a few attempts to get it because my axes were either overshooting the target or not going far enough.
Eventually I did it on Aftermath, I was at C flag, just chucked 2 towards A flag and got a guy who was running up those steps from A flag.
It was magnificent to watch back in theatre mode haha.
I was also trying to get this challenge for a while. I got mine on Turbine (i like to call it Turdbine because it's a garbage map). Regardless, I threw mine from where you can hop on the fallen Turbine and start to walk up it, to a guy who was spraying the mounted machine gun in the room. The distance has to be pretty far. I got a few long tomahawks that, to my surprise, weren't longshots. Just stick with it.
I don't know if you use the Wii mote or the Pro controller, but i'd recommend dual analogs for this challenge because it's easier to keep steady. May try sticks and stones as well, and try to get lucky with an AFK dude?
I use Wiimote, been getting better with it on close/medium fights, I can actually hit on the moving targets, it is hard though.
Sticks and stones sounds like a good idea, but usually at the times I'm on there is only gun game matches.
I have a feeling that I should go into groundwar, I see plenty of people stacking into one spot to sniper etc.
Thanks for the tips, I shall go and make a class