There is a wide variety of pouches to carry different types of ammunition. There are numerous ones to carry pistol and rifle ammunition, specifically M4/M16 magazines. They can be attached to a belt or to the molle webbing of a tactical vest. There are also pouches to hold loose shotgun shells and some to hold rifle cartridges in individual compartments. You should be able to find options for whatever you want to store and carry with you, securely and conviniently.