When getting a scope for 1000y usage you will want something that has plenty of internal elevation. This will usually be the 30mm tubes but some of the 1 inch tubes will have enough.

You also want repeatability unless you plan on using it solely for one distance.

If you have a rifle that has plenty of recoil, be aware that most scopes will have shorter eye relief as the magnification is increased.

Another issue to be aware of is that most scopes now days have rather short tubes. Check the length of the tube unless you have off set bases.

I have been using a Leupold Vari-X II 6-18X40 AO Target with fine crosshairs for several seasons. It's a great scope with lots of good qualities and priced around $500.

The fixed power Weavers are also fine scopes.