I had a four year old Vortex Diamondback 4-12x40 mounted on a .243 that suddenly lost the ability to maintain its point of impact and would not adjust properly and then would wander around the target. I sent it in to Vortex and one week later I had a new scope on my doorstep! They do stand by their products and honor their warranty! But the concern I do have is I didn't do anything out of the normal with my scope when it failed. I hunt off my atv and have it in a kolpin gun boot between sets and that's the most bumping the scope has ever endured. They said in the repair write up that there was damage to the tube from over tightening of the rings and the reticle was canted with debris in the scope. The thing I don't understand is that there were no ring marks or visible dents from the rings whatsoever on my old scope when I sent it in. Is it possible to damage the tube by over tightening the rings without causing any external damage to the scope? Thanks and happy trails.