French artillery

[DFlynSqrl]

Very nice!

[d_Guy]

.... I will consider it a variant consequence of the tough campaign.

I like this answer. The captured Prussian guns is a good story also. I suspect (most of my knowledge of chemistry has left me) that there is more than one possible path for green paint to weather to lighter blue. 

[Westmarcher]

.... or re-painted captured French guns re-captured.   

[Jesus]

 

[Leman]

It's all about the narrative.