I have a farmer friend that gave me a awesome target bag. This bag is huge 4ft byt 4ft and was used for bean seeds to be delivered to farmers. You can get these at FS dealers that supply farmers and I was told they throw them away. Your not going to be moving this thing around much but I set it up in my yard and it stays there just like a target butt. I got plastic from a local factory that makes plastic packaging and they where also throwing it away. From there I painted circles (you could paint or tape anything you want on there) and it stops arrows great. By buddy has shot his thousands of times in the last 4 years and its shown little wear. All plastic nothing rots, and you have 4 sides to use if one gets too shot up. Total cost for this target is about 2 hours of my time.
