I wondered about the pressure, but it's based on the .40 S&W which is a high pressure to start with. From what I've read that bottleneck design really lets the round funnel into the chamber well.
The price issue I can certainly understand, but wonder if that is a chicken or egg issue? Ammo costs a lot because they don't sell a lot. If they sold as much .357 Sig as they do 9mm wouldn't the cost be significantly cheaper? And if it was cheaper wouldn't they sell more?
Just speculating, again, I have no experience at all with this round, just wondering what others knew or opined.
