fireman

I am new to 3 gun and I have some questions about the trooper class: 1. Id like to run my fixed optic up close and a variable for long range. Can I change optics on my rifle during a match? 2. Are drop leg AR15 mag pouches ok to use? 3. Can I use a heavy metal rifle on some stages (long range!) and my AR15 on others? Thanks for the information.