Two straight years running I lost a scope on my 375 in Zim. Couldn't zero. Adjustments had no effect. Mounted spare checked zero and continued to hunt first year. Second time just switched to my 30-06 for remainder of hunt. Both scopes were Leupold Vari-XIII 1.5x5's which were returned to Leupold for repair which they promptly did,one under warranty and the other which was many years old they upgraded to current and returned for I believe $15. Have used both scopes many times since with no problems. My first safari of 8 I had the scope on my Brno 602 375 shift to rear because the Warne levers were not tight enough and the lug on rear ring that fits in the slot in rear bridge tried to shear off as it had minimal engagement. I prefer the CZ factory rings as they fit better for this reason. The lug is heavier and fits the recess better. Haven't tried Talleys but am going to buy a set and see if they are better. They certainly LOOK better. I always carry a spare scope.