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That's a hard question to answer because there are a lot of variables to take in to consideration while shooting extended distances. From personal experience, I shot with a friend who uses this Vortex Razor HD Gen III 6-36x56mm Rifle Scope and he has used it to shoot 800 yards. Here are some guides that give more information into long range shooting and rifle scope selection:
https://www.opticsplanet.com/howto/how-to-start-long-range-shooting-on-a-budget.html
https://www.opticsplanet.com/howto/how-to-choose-a-riflescope.html
My three shooting buddies and I have been on target out to 2000 yards using the Razor HD Gen 2. We did a mile with ease. 4 shooters and all 4 of us were on target at a mile then we moved to 2000 yards and we were on target still. The Gen 3 should be able to do that and more. However, scope is only one piece of the puzzle. Gun and setup, Ammo, suggest a 20 degree rail, dope, and conditions will each come into play when you get past 1000 yards.