I have been shooting for over 50 years, and can say I have been a marksman for over 40. But I have only in the last 15 years been a continuing student of “defensive” shooting.
I am an NRA instructor in almost every discipline the NRA teaches, but my real defensive shooting has been through professional schools like Front Sight, Nevada. I am not a combat master by any means, but I am a distinguished graduate of a few of their defensive shooting courses, and have advanced tactics training.
For pistol courses, everything at the school is done from the holster. A typical test is controlled pairs to center of mass from the holster in under a second, maybe 1.5 seconds as range increases to beyond 20 yards. You learn from the git-go how to draw properly and not muzzle friendlies, how to be aware before the fight, survive the fight, and not get shot by late arriving law enforcement after the gun fight. Malfunctions are drilled so that handling them is instinctive, day or night. Night shooting involves managing both gun and light. The list goes on and on.
I currently live in a state/county where the county will not issue CCW (unless you are a politician). So I had years of training before even considering a CCW. I took the Utah course, which still doesn’t help me in my state, but seemed like a good thing for traveling. As I said, I was pretty unimpressed with the competence bar set for people to obtain a permit. While being accurate and fast is important, knowing how to run/fight the gun, and stay alive after the fight are probably just as important if not more so. None was required for the CCW permit.
Well, I hope you keep your AR15 with loaded magazines in a grab and go case, unlike the fellow in Sutherland Springs who had to load his magazine on the run -- barefoot!
Here in Phoenix we have some excellent gun schools. Although I've not been to Gun Sight, I have trained under James Jarrett (ASA/USMA) and George Dean (TacTrain). I see that Jarrett is now director of NRA Carry Guard. I'm glad things are going well for him. Some of my fondest shooting experiences have been on the line in his courses.