I purchased an exd reticle leveling device from brownells and it really showed me I was off on a couple of my long range rigs, I don't know how one can mount a scope on a long range rig without one. one thing that it doesn't say is, when the device is on, you can look right through the slot in the device through the scope and line it up with something that is square, I used my back neighbors front door that is about 150 yards away. it was also vital in helping me mount the scope level that flips up. its expensive for what you get, but sure does work great, I will use it to mount all my scopes not just my long range rigs
