Here are two that I use. The small one attached to the Picatinny rail was used to level the action. Then I used a Vortex side level on the scope to match the first one. This way I can look through the scope with one eye and watch the level with the other eye. I later removed the lower B-Square level.
Thanks for the input. When I first got into long range and bought my Nightforce optic, I had no idea everything that goes into making a long range shot consistent. The guy that sold me my scope mounted it. He used Leopold removable rings. I like the rings but I had no idea the importance of the scope level. When he mounted the scope he didnt do a very good job leveling the scope. I placed a level on the picatiny rail and the level on the top of the scope was way off. I was having to hold about two feet left to hit the center bulls eye at 1000 yrds. I looking forward to getting the the range to see if my adjustments are on and consistent.