I try to stay with at least 1MOA target size. 2MOA is better for those nasty long distances. It's a lot easier to correct for a sloppy hit on a 2MOA target than a complete miss on a 1MOA target. That said, a 40-something inch wide circle is a lot of steel to hump around. The 18" gong might not be perfect but it'll work out to 2k if you and your kit are up to the task.