From the Connecticut State Library collection of Colt Firearms Co. photos on Flickr is this photo of a M1895 Colt-Browning machine gun mounted on a motorcycle side-car. In the photo one can see how the wooden ammunition boxes for the MG are stowed in the side car. Also there is a hand crank MG belt loader with a vertical cartridge feed trough on top of the ammunition box stowage compartment. View the picture in a larger format (while in Flickr) as the detail in the image is very good and the belt loader shows up quite nicely.
Here is the web address for the Connecticut State Library collection of Colt Firearms Co. photos on Flickr for those who want to view the many other images there: