My only advice would be to stay lean, based on the RBGC 5k run and gun. They were some crawling through rope/string/spider web type stuff and a low crawl. You can keep a few mags on you and extras mags or loose rounds to top off mags in your pack.
IIRC the guy that won that event, used like 3 of each rifle/pistol and just topped off from his sling pack while moving between stages. Him being a good runner and shooter also helped, but I always try to learn from others. Just don't leave a trail of AK rounds to tease me like bulletpaluza lol.
Those were bread crumbs brother I was showing you the way.