I've never done an actual endurance test between Caspians cast and barstock frame so I can't really answer that question. However I've built a lot of custom guns using Caspians cast frames both in single stack and double stack variety and I've never had any complaints from the customers that have them. I might add that most of these guns are used in some form of competition and are subjected to high round counts using major power factor loads. I would not be concerned whether the frame is cast or barstock, I believe either will hold up well and I believe Caspian has a good product. Also I believe you will find Gary and his staff a pleasure to do business with.
(816) 675-2340 www.huntercustoms.com
Gary will correct me if I'm wrong, but I believe he once said that he has never had a cracked or otherwise broken cast frame come back to him. Caspian built their reputation on cast frames. I wouldn't be concerned.