Use aluminum shafting to foot and collar your carbons and you can shoot the most solid stump you can find and not damage your arrow. I have hit rocks here in Mo and had my arrow bounce back my direction and still be ready for the next target. Will email photos. Haven't learned how to post them here yet.

I use just about any arrow for stump shooting. Right now I'm using woods and rather than using field points I've switched to blunts. A field point, because it is basically a cone will try to steer around a hard spot in a stump or log or whatever and the result is often a head broken off. Since I've switched to blunts I've not had this problem.

With carbons I just put a small flat washer (fender washer) behind the head and have at 'er. I will sometimes reinforce the tip end and nock end of the carbon with a short piece of aluminum shaft.

Where at in California are you.?  There should be ground squirrels by you someplace. They are great targets and you can get them all year. Farmers hate them they destroy tons of crops. And you destroy just as many arrows chasing them as you do on stumps. OK a bit more arrows die trying to get them little monsters. I use carbon with an aluminum boot blunts or judos.