What do they look like? I haven't seen any I ran out after getting the wheel for the steam pipe. Iirc that's when the first attack happens.
They look like white little white boxes of bullets (didn't have time to texture them during the jam), after the first attack you find a few boxes after passing the steam pipe in the office to the right :) Hope that helps, if you have any further questions a walkthrough can be found here Walkthrough - DESCENT by ChristophGray (itch.io)
I'm going to pin this to the about section just in case people miss it as there have been multiple logs since then.