I built my own on our family ranch in west Kern county. I put a couple of sturdy wood benches and some nice target stands made out of green wood that I got from Lowes. The design was found on the internet and I made one of them to fit my height. Just buried the legs 18" in the ground and have never had a problem with them. There is a 15' tall berm that surrounds the ranch from the neighboring water districts' leaching ponds, so I don't have to worry about a backstop.
As far as local laws and regulations; fortunately I live in one of the last remaining conservative areas of California, so local sherriffs are cool. I never have had a problem and did not get any permits. I guess its easier to ask for forgiveness than permission. The law was called when I first put it in, one day when my buds and I were practicing 3-gun with our pistols and AR's. Since they were met by a locked gate and I was not in city limits they could not enter. They waited for me to leave and when I talked to them they knew my Dad from the farming community. I offered them to look at my weapons and they only wanted to see the AR's. They never looked at the evil features and just wanted to compare guns and know where I got some of my parts and furniture. They said someone called about automatic rifle fire as to which I told them tell that person thanks for the compliment because its cal-legal.
Hope that helps.
