The OP said that initially his gun range would have had the newly built house downrange of it, so he moved the range and bought more property.
yip, my bad. I'm used to outdoor ranges having a large dirt berm behind or shooting into a hill, so generally speaking just using the planks makes me a bit uncomfortable, generally speaking, but no big deal, I think the OP did a nice job.
Do you need to worry about bullets deflecting back at you? What's the minimum safe distance with pistol rounds? (.380 - .357ish)