Lately I am instructing full time. Like most readers, I own a number of firearms: some for hunting, some for sport, and, of course, others are kept for defensive/duty purposes. I found that what I needed was a pistol that would be first and foremost a training tool. At present my number one defensive pistol is a Glock 23, so choosing a Glock for a trainer was not a difficult decision. My next question was which model?