The challenge seems so easy, I don't understand why I can't pass it. It requires 3 shotgun kills without reloading. I've done that a million times. I've tried my patriot elite, my sniper defender II, my Zru smg ... And I kill 3 on the same clip but it doesn't pass. Perhaps there is a bug with the app?
Or am I using the wrong weapon? Please...any suggestions would be appreciated!!!
Btw I am on level 16, chpt 9.