How to Build a Shooting Barricade for Under $50

Just wondering, do you really need detailed plans with nice straight lines for a barricade? Seems to me imprecise would do just fine.

I have access to basically an unlimited amount of pallets. I currently have about 45 of them in my back yard and probably 15 in the shack at the range. They come with banding slats. 2 screws and now you have legs to stand them up.