Your task to get this reward is that destroyed sniper pistole. I recommend choosing location you can see in the video, as it appears in the towers a small number of enemies. An enemy who is under the tower properly and then kill gun sniper on the tower. I will be very glad if you start subscribing to the channel. This will support me in translation trophies, achievements and turning these video tutorials. If you can not get the reward, let me know in the comments. I will gladly help you. If you guide a little help, or have already earned a reward, surely leave a LIKE! I wish you luck, to gain additional rewards!