It doesn't seem to me like you have anything to lose. Being a poor boy, I have done the screw/lapping compound a few times and it seemed to work for me. I have also just stuck a cone shaped stone in a dremel tool and ground on a couple that were really bad. Groups went from from terrible to not so bad. If it doesn't work, you can still have a gun smith cut new one in a lathe. Have you priced the kit from Brownell's that cuts crowns without a lathe? It looked interesting to me, but I don't know what it costs.
good luck, Cody