1) A change on the battlefield? For most of the war, the principle artillery that Russia has been losing have been Self Propelled Guns (SPGs) (gray) that seems to be changing, with a larger proportion now being Towed guns. (orange)
2) This is based of the Visually confirmed numbers by @WarSpotting a table of which is below for each month of the war, with the above graph being a 3 month average, looking at just August only 1 of 11 artillery systems has been an SPG.
@WarSpotting 3) I don't know why this is, I can think of a few possibilities, including that it might just be random and return to nonmail soon. it might be Unkinan targeting and/or reporting. or it could be Russia, possibly pulling their remaining SPGs back from the front line.
@WarSpotting 4) And mostly because I like this graph, here are the calibers of all the lost guns (towed and SPG) over time. notice the big rise in 122mm (light blue) recently?
@verekerrichard1 using relative numbers is distorting for no reason, why not use absolutes?
@verekerrichard1 Overall trend. Big slow 152mm platforms are in drone range now. So they pull them back. Or they have none left because they are concentrating on other things like tanks and IFVs? Or they can't make the barrels anymore? Who really knows.
@verekerrichard1 Towed guns are easier to manufacture, smaller caliber takes less time milling. Shoot and Scoot is dead in the time of drones so why waste resources on refurbishing or even manufacturing SPGs?
@verekerrichard1 Straightforward answer - they are running out of them do to a combination of kinetic and maintenance losses.
@verekerrichard1 One factor might be that artillery is now mostly working dug in and camouflaged, which is a) easier for towed artillery but b) increase the survival rate of armored SPG even more.