Bring a pistol you know works, can run hard and you enjoy shooting repeatedly. Typical carry pistols like Glock G19s, Smith & Wesson M&P9s or Springfield Armory XDs are great. You can bring a single-stack pistol, but expect to perform a ton of reloads, and students should bring at least five magazines.
The course focuses on drawing a lot, making a good outside-the-waistband (OWB) holster and double magazine pouch essential. Three double-stack magazines will also do just fine. You can wear eight magazines on your belt if you want, but it is not necessary. Tactical rigs are also fine, but flimsy holsters are not going to work here. I used both my Safariland rig and my Strategic Tactical Group Kydex, and they worked perfectly during the course.
Students will shoot 1,500-plus rounds during this class. Bring a cleaning kit and some oil since shooting as much as 800 rounds in a day will get your semi-auto pistol heavily fouled rather quickly.