I tried the ATN first gen night scopes and had to send both the first one and its replacement back because they would not hold zero. Too bad because the night vision part was pretty good for what I wanted. Ended up getting a second generation tube, the ATN PS22. It fits either on a picatinny rail in front of the scope or clamps on the scope itself. That way, you use the scope already on the rifle and no need to sight in or depend on the night scope to hold zero. I know you asked about first gen, but in my experience, you are better off heeding Graybeard's advice and saving for a gen 2. I can see 200 yards with it, and the infrared is nice as it really lights up the eyes. Works great, and I had plans on using it this last hunt. However, I found that after hunting during the day, I am getting at the age where a warm bed is more enticing than staying up half the night.