Originally Posted by
sinister
In specific military shooter courses you will shoot for weeks (daily) "Clean," with a minimum of equipment to get the basics of shooting down before adding gear.
Stuff is added in increments -- Army practical training methodology is crawl-walk-run.
Three-day commercial classes (Friday - Sunday) really aren't long enough for a decent shooter to require being "Jocked up" complete with armor and Dome of Obedience (especially in the summer). It may help for people to consider how they configure their stuff -- where are my magazines, do pouches interfere with mounting the carbine, or stowing it for pistol transition.
There's a pain-in-the-ass cost to wearing stuff, and it can detract from training once it interferes with learning progression.