For many who go afield each fall, the traditional belt-worn leather cartridge box is the carrier of choice for extra ammo while hunting. These cartridge carriers are time tested and dead tough rugged, and they offer an opportunity to add a few "extras" to what is normally carried afield.By cutting the cartridge box down by two cartridges at one end, you allow room for some other essential items besides ammunition. Often times, we leave our vehicles, or even from hunting camp, less prepared than we should, and the daypack or fanny pack are left behind.
A few items to consider carrying afield in your cartridge box might include, toilet paper, matches, fire-starting material, fishing gear, instant coffee, a wet-type disposable towlette, extra AA batteries for flashlights and a butane lighter, all of which will fit nicely into the extra space of your leather cartridge box.

The small packet contains waterproof matches (from GI issue MRE's) wrapped with thirty feet of 6 lb. test monofiliment fishing line, ten baitholder fishooks, a couple of brass snap swivels, and about a dozen BB size split-shot sinkers.
The packet of toilet paper is also from GI issue MRE's as is the moist towlette. All of these items fit into a small, flat zip-lock bag the width and hight of the cartridge box. This fits into the back part of the leather cartridge box as shown below.

The strip of rubber inner tube is folded in half, and placed between the front flap and the cartridge carrier while the two AA batteries and the butane lighter ride nicely where the cartridge carrier was reduced by two cartridges.
Once the "extras" are loaded into the cartridge carrier, it is no heavier than if carrying twenty rifle cartridges, and not appreciably more bulky, but very much more useful! Give the idea a try and use your own variation of added gear!