I want to build a 9x23 defensive type gun with a high cap frame. Which frame would you guys say is the best to use for a new project? I have an SVI gun that I like very much, but getting something from SVI is impossible. What about a new Caspian machined high cap frame? I have an old first generation cast frame Caspian that has been a good gun. I have no experience with anything from STI. I would appreciate any advice.