Buy a Colt Delta Elite, swap the barrel for 357 Sig...viola...you have 357 Sig in Colt body...the 10mm mags work fine for 357 and the 40 rounds, or you can get (the very rare) 40 cal Colt mags for around $60 each

I thought that the Rangers were issued the p226 in 357 Sig, but were given the option (for the Rangers, not the rank and file of the DPS), the option to carry a personal sidearm of approved form....not from personal experience, but from conversations with a now retired Ranger.