Abstract: There is great interest in the design and manufacture of lightweight weapon platforms that have capabilities near to existing heavy armour systems. This quest initially started with the requirement to transport field artillery guns via helicopter. With the change in the global situation, the threat has changed and new enemies have developed. This has given birth to rapid deployment forces capable of being effective in a short time. Naturally this force has to be highly mobile (fly light), with its direct-fire weapon platform being able to be delivered to the theatre of operations by C130 or A400 type aircraft. This has imposed serious limitations on the overall weight of a piece of equipment, limiting it to 17–25 tonnes. On the other hand, it is desired that the firepower of this platform matches existing systems. The aim of this paper is to look at some existing guns, having a bore sizes in the region of 105–140 mm, and their mounting on a light platform (17–25 tonnes). Work reported here concentrates on highlighting some of the important constraints that exist and possible ways of dealing with them.