I've been using an open top tool bag. This one: https://www.amazon.com/gp/product/B0788VGQMV/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
What's neat about it is the small parts bin that zips into the bottom. I took that out, and it fits a small plano hard plastic pistol case perfectly. There are lots of little pockets for tools, granola bars, asprin etc. And the three large spaces are great for ammo boxes. There are two clipped straps that hold my hearing protection and a spent brass bag and it's just big enough around that I can put my competition belt on top of it, pick it up by the handle and carry everything in one hand. The only downside I've found is that there is no protection from rain.