I would buy something else, save a little more and get a better brand, Vortex is not that good in my opinion, especially their lower end scopes, I owned a Viper 6.5-20x50 and was very disappointed in the clarity, had blurred edges and all. Was not much better than a Tasco.
You shoulda sent that back to Vortex. They would have made it right. That is NOT a common problem with the Viper line