An adjustable reservoir for articles such as smoking articles and smoking article filters comprises a plurality of conveyors mounted one above another in a vertical stack, each conveyor comprising an endless belt defining a curved conveying path of constant radius extending between two ends proximally spaced to define a gap through which articles carried by the belt may drop, and a drive mechanism operable to rotate at least one conveyor about the vertical axis of the stack so as to change the angular position of the gap of that conveyor relative to the gaps of adjacent conveyors. Changing the relative angular positions of the gaps allows the capacity of the reservoir to be adjusted, and further adjustment can be achieved by changing the direction of travel of the conveyor belts. The drive mechanism can be configured to move one or more groups of conveyors in unison, or to move each conveyor individually.