The withdrawal of Russian troops from the Caucasian Front after the treaty of Brest-Litovsk left a power vacuum in the eastern Black Sea region. The Andreivian state quickly moved to reconstitute its army using whatever military hardware it could acquire.
Improvised vehicles were common - this artillery supply wagon for example...
The ubiquitous French 75 was widely used by Andreivian artillery units.
The Andreivian People's Horse Artillery (formerly Royal Horse Artillery) wore brown busbies with cobalt blue bags.