Hit a orange plate on slow spinning wheel far far away with Arisaka Type 99 blot action rifle. Time limit : 10 seconds.
This is an easy challenge, just wait for the orange plate moves into your sight then pull the trigger.
The hardest part of the challenge is that the target is so small and difficult to see. Here is a tip, right before you click on "Begin", you right click on screen, a menu will pop up, select zoom in, then click on "Begin". Once the challenge begins you will notice everything is magnified, it is like you now have a scope on the rifle. After the challenge, right click and select show all.