It’s standard Air Marshal ammo. Moves fast, hits hard, shouldn’t need a followup, limited penetration. Costs a lot in both ammo and the barrels it tears up in practice. It’s what you buy when price is no object but performance & availability is.
Yep. I just had the pleasure of taking a class from the guy the Air Marshals chose to instruct them. They did an extensive testing program for specifying the caliber and came up with two recommendations: (1) .357 Sig, and (2) .45 ACP. Great, he sez, I'm gonna get to instruct on .45...oh, no. These guys had money. REAL money. When they carried in the crates of .357 Sig he said he was thinking Wow! I get to teach with that, and then, Wait a minute! I PAID for that!
They're good shots. They have to requalify every 21 days because they lose their edge after that. That sort of program costs a lot of time and money. Did I say a lot of money? When they need to train in a 747 they lower one from the ceiling. When they need a 707, same story. These guys have money. Your money.
Costs a lot in both ammo and the barrels it tears up in practice.