"Caisson" is an ammunition wagon in French. The French army of the 1770ies was well organized. While other armies still depended on civilian wagoners, even for moving their guns, the French artillery had its own corps of drivers who wore a special uniform of dark blue with light blue facings.
As the new rules our group is developping, demand vehicles of supply for guns and infantry, I had to activate some parts from lead mountain.
Fortunately I had bought a slightly damaged model of a French "caisson" with spare wheel at the Kulmbach Fair some time ago. It was produced by Zens Nürnberger Zinnmodelle, a firm that has been extinct for some years. Their models are detailed and historically correct - only they are hard to find these days. I assembled the model and painted the wagon the traditional French blue and black of the period. A drover from Minden Minis was painted as a French artillery drover in his sleeved waistcoat (without any further changes that would have been possible). And the heavy draft horses came from Front Rank.
The base was modelled as a typical road in America.