At 1000 yards I like to use a 12" target. It is a little more than a MOA and not too terribly difficult to hit. At that distance an used disc blade is adequate to use since even though it is a poor grade steel nothing should punch through at that distance as long as it can swing when hit. Generally they are larger than 12" and are somewhat easy to come by depending on where you live.
If it is under 300 yards I like to use AR500 steel, because I sometimes use my 22-250 and speed is what damages targets.