A great design as it is, the 1903 Pattern belt had one small problem when used with the military equipment of the day = no rear mounted buckles for attaching the 37 Pattern webbing cross-straps.
To get around this, there was a small canvas 1 3/4" slider developed, fitted with a pair of 1" brass buckles;
the belt was slotted into this, thereby allowing the shoulder straps to be attached to the belt.
A simple solution, which got the job done!
An original 1942 dated example.