Any high mag LER scope takes time to get used to. I have used the 3-12 on 12 power consistently for both bench and field shooting (prone). I shot over 400 round from the prone position at 12x with targets ranging from 200-800 yards this past August without any problems. This was with a center-grip XP. Rear grips with the 12x are easier than the center grips since most people need a extended base to move the scope further forward on center-grips like the XP-100. Software like Exbal should allow you to change your magnification and use the ballistic plex reticle. If not, you can choose the distance you want your last plex sighted in for and sight it dead on, then work your way forward and determine your other plex points. Even with Exbal I confirm the software with shooting at the actual distances. I have a number of 3-12's and I love them. Everyone has their preferences, and this scope is not for everyone. If you want high magnification though, it is the only scope that has a LER, unless you go with a Siebert conversion (14x & 20x LER's).
Harold,
Sorry I have not responded. I did get your e-mail, I have not had the problem you mentioned to me. I keep my magnification on 12 power when hunting and competing so I wouldn't have had the problem. Once warmer weather comes again I will play around and see if I can replicate your scenario. I would contact Larry @ Burris, tell him about it and ask if he will check it out himself.