You can shoot stuff with just about anything. A 3-9 will work, but it's nowhere near enough power. A 3-10 or 4-12 will work too but if you're serious they're nowhere near enough either. And for shooting prairie dog sized targets out to 400yds, forget it. It's all about having fun.....do it right and enjoy things a lot more. Get a scope that goes to at least 20X and a 6-24 is better. At 400yds, 24X is like 6X at 100 .......6X is about minimum for small targets at 100yds. At 400yds, 9X is like 2-1/4X at 100.....would you be satisfied with that? Realistically, you'll be shooting a lot more targets at 200-300yds than at 400. At 200yds, 24X is like 12X at 100 and that's not too much.