There are two ways to mount larger-than-normal missiles for spaceships: a spinal battery that takes up one system in each section; and an oversized battery that takes up three systems on one section. Here is a third method that increases missile calibre while reducing the ammunition. Because the system size does not change, it can be applied to individual missile launchers in medium, secondary and tertiary weapon batteries. Each calibre increase "step" (e.g. 20 cm to 24 cm) divides the ammunition count (rounding down) as follows: