Lagopus,
Your experiment with the Ithaca 37 duplicates what I also found to be true with steel. I do suspect one could make an argument that steel works very well for clay pigeon sports, but, the range it is useful on with actual birds is a pretty narrow band.
I have a few guns usable with steel shot, but, I suspect my heart will no longer be in the game if I'm forced to use it for everything. I'm also sick of being sold junk science on topics of interest to me, and then being told how I will go about living my life, based on the junk science.
That likely has as much to do with my thoughts on using steel shot, as anything else.
Thanks for posting your experiences with the loads in the clarity that you did.
Best,
Ted