I'd also say about 2' though that might stretch it at the edges

fill up some of those milk jugs with water and scatter them around a field, they're loads of fun to practice shooting with field positions, lots of feedback when you make a good hit

as gs said, if you can hit them consistently, you'll make good shots on an elk kill zone

I've wondered what the people at the recycling center think when they see my piles of fragmented, shredded milk jugs [&:]