I suspect they have always worked. In buffalo terms.i further suspect.they were particularly useful when breaking down said bovine. Imagine a 300 grain solid hammering you through the shoulders at 2400 fps. I suspect if.it did not put you down, the shards of bone it blew throughout your thoracic cavity would have I. Short.order. I bet someone who says they dont work has never seen them used.
I'll take that bet.
I've killed buffalo on three continents. Most in a day was 28 which I've done twice. Most without moving my feet was fourteen. Most in a week was 111. Best combined day (Three shooters) was 81.
What do I win? Never mind, you wouldn't pay up anyway.