I've had the CDI for the better part of 2 years. From the get go the Diamond sights are <moa/moa. I have had the barrel off 10 times or more and never once have I had a problem with holding zero. One does need to accuratly line up the 12:00 rails. I had made it my own with a change of grip, the addition of an Eotech 512, bad lever, trigger guard, bipod (sometimes) and rails at 3 and 9. The rifle is as tight as the day I purchased it and anyone that shoots it is an instant marksman. I keep it clean shoot only 193 or 855. The lifetime warranty is transferable!!!