I cut open one Hevi-Metal 1-1/4oz. size BB because that's all they had left on the shelf for 3" 12ga. goose loads at the local farm and barn. I wanted 3" 1-1/4oz. Steel BB, but they didn't have it so I splurged on the extra ten bucks a box and settled on this stuff-
47 pellets of bismuth with one ten count average weight of 4.35 grains per pellet for a total of 204.5 grains or about 15/32 of an ounce of bismuth size #2 or thereabouts.
48 pellets of 6 grain per pellet steel BB for a total of 288 grains or about 21/32 of steel shot.
The rest is flax seed on top of the bismuth. There is a bit over 1-1/16 ounce shot total. I haven't patterned one yet, not sure what range to pattern it at. When is what pellet going to pass up which?
I wonder at what range the duplex of #2 bismuth and BB steel might be most likely to be effective.