The hardness wouldn't bother me if the batch I have was round; I'm sure the squirrels wouldn't notice the difference.
I tried to photograph a few to show what I'm talking about, but, I couldn't get my camera to focus on the little buggers good enough to show the deformation that I'm talking about. The "belt" is not uniform from buckshot to buckshot, but is evident on most to some degree. It appears as if the two halfs of the swaging mould didn't quite line up. Maybe I got a Quality Control day off batch.
My intention was to make a frame with heavy plate glass to roll the buckshot to see if I could smooth them out, but, that project is in my procrastination file. Luckily I came across a couple of boxes fo .350 round ball at swap meets before the world changed and don't have to use the buckshot for now.