capturing would be of little use as Ukraine doesn’t have ammunition to them, or even a way to get more. Efforts to get Ukraine more artillery ammunition are focused on NATO standard rounds which will not fix in these.

This is the typical days haul of artillery for a long time. However Russia is known of have a lot of artillery in various stockpiles. The number destroyed isn’t the point so much as it forced Russia to go back for even older artillery to replace it. Already we see them using systems designed in WWII (AFAIK nothing that saw service in WWII, but things designed then and built after the way).