I have shot, pattern and penetration tested a lot of steel shot over the years and I would never shoot steel shot at live animals if I had an option to use one of the heavier metals. Save your steel shot for waterfowl, or sell it to someone who will use it for that purpose. Get some decent buffered lead loads, or Hevishot, or similar tungsten based shots.
With the time and money for gas you will spend trying to find them, you owe it to yourself to use something which is effective for that purpose, particularly if they show up, just a bit further than you thought.
Steel shot is second rate crap, and the only reason any of us use it for waterfowl is because we can't legally use lead or justify the expense of the more expensive tungsten based shots. Steel gets the job done on waterfowl, but only because the ranges are short and the birds are not nearly so heavily constructed as mammals.