Gunslinger/ Pistol MP challenge

#1Cicatriz_ESPPosted 7/9/2014 7:51:16 AM
This MP challenge requires you to kill a target that is running or jumping with the hidden gun.

I know this can be done in wolfpack because I've managed to get silver after a loooong time. Now I need to get 50 more and I still don't realize when the target is properly RUNNING. I mean, I shot them when they are running after/from me and it does not count towards my total, most of the time.

What is the correct way to do?
Sephiroth kills a lady and white materia drops to the floor. But when Cloud mows the lawn, it's brown materia that drops.