One piece of additional advice: I have owned several xbows and sometimes I had a real hard timing getting good groups. Other people would say they had 2 inch groups at some distance and I would be at 4 inch. Ultimately, I figured out I was canting my bow. I was surprised how much of an effect that had. So, now I do the following:
When putting the scope on:
1. Put the bow in a gun vice or rest and place a level across the limbs. Make sure it is level.
2. Put the base and the bottom of the rings on and sit scope in the bottom rings.
3. Take off the cover of the elevation adjustment and put a small bubble level on it.
4. Make sure both levels (on the limb and on the scope) are leveled. Then, screw in the rings. Careful, you may need to re-adjust as you crank down the screws.
Now I know the scope is perfectly level.
When I'm sighting in, I put the gun in a field pod or other rest. I keep the elevation adjustment top off and I put the bubble level on the scope. I make sure for each shot, I have checked the bubble level. That has made a big difference and made sighting in easier.
In the field, I don't have a level to use (although they make some, I can't get one that fits on my scope), but at least I know I'm sighted in correctly and its just up to me to keep it as close to level as possible.