as shotgun shot gets lighter, it takes bigger pellets to get the same energy to pennetrate to the vitals to kill/knockdown a critter.. remember birds have a layer of feathers that resist pennetration to some degree.. its thicker in winter.. this makes several problems.. steel density is lighter than lead so it sheds velocity faster than lead shot of the same size.. if you increase the size to get the same energy at hunting ranges, its larger size reduces pennetration more than the smaller lead counterpart.. this is offset in modern guns by using higher velocity, 1300-1500 fps if possible.. a decent killing velocity for lead is in the 1150 ft per second muzzel velocity range (modern guns).. your steel shot load could very well be in the 950- 1100 fps possibly more if your experienced, and not out in cold weather.. for these reasons steel shot isnt a good choice in muzzeloading shotguns in my opinon.. if you go up one size in lead or a little more with bismuth it gives you similar results as with a modern gun but at bp velocities.. i havnt tried heavy shot, and if you can keep fouling under control, so the plastic wont give you blowby after several shots in your hunting conditions, then it could work fine.. but pattern pattern, pattern, also again in the weather you plan to hunt in.. check pennetration by shooting a campells soup can with modern gun you are having success with on the bird you want to hunt.. match pennetration with your muzzeloader with shot that works similar in pennetration and pattern at yardage that this all comes together and this is your max range.i have better luck with body shots with black poweder than wing shots with single shot smoothbore and cylinder choke.. this makes all this above very important.. a choked sxs shotgun works very well with black if its done right and isnt as picky or problamatic as a cylinder bore.. the second barrel with full choke is wonderfull for finishing off birds youve knocked down.. .. dave.