These discussions are ALWAYS the same. "I've had several Leupods fail. They're junk and I won't use them anymore".... VS..... "I've hunted Leupolds all over for decades and never had a problem". Nobody knows why any scope fails. Nobody knows why one brand is or may be better than another. Nobody ever pulls any scopes apart and tries to figure out just what the weak and strong points of one brand over another are. Until somebody does, it's all just conjecture and luck of the draw or lack thereof. I've even read of Nightforce and SWFA failures right here on these forums. With SWFA's it seems the 1-4'X's are more prone to failure than any of the others. I'd think the internal components would be the same acroos the line. You roll the dice and take your chances. While some may be less prone to failure than others, none are 100% foolproof. That's the way it's always going to be with anything mass produced and made by human hands.
