You learn something new everyday!
Thanks for the info Chris,
I thought I had the russian guns pretty much covered but Ive obviously missed those ones, I must admit I have never seen any "in action" photos.
I have, however been to the museum in St Petersburg but dident notice the strnge 57mm version, shame on me!
As I stated earlier we need better references on artillery, not only russian but also british and othersm but the lack of ibfo on russian ertillry is huge,