That rifle looks like it has a suppressor on it, so it is not the loud one, correct? Did you get a photo of it?
Why do people practice with pistols at the range? I practice in case I have to shoot someone.
Weaver stance isn't as steady and low as isoceles. Have you considered those differences?
I recommend people practice for fighting, so you fight as you practiced. Standing straight up in a gun fight is a bad idea.