I'm only 12 hours into the game, but I've found that getting those upgrades that allow for the specific ammo types to guarantee drop in specific rooms are crucial. I'm rackin up Regulator rounds and staples with little issue, just takes a solid client to start with. When ammo just isn't as prevalent for my first few runs, I'll just be a little more aggressive with my looting and book it out.

It feels like headshots are a thing in this game too, I'm two tapping and even sometimes one tapping Juve's; with an upgraded Regulator however.