Model 57 S&W .41 Magnum - the "old man" showing me how it's done.

Handloads with Unique Powder.
I can't remember the bullet weight, but it was at least 210 grains - though I want to say it was 215. They were lead-cast bullets made from weight weights.
IIRC, when we reviewed the footage, two shots actually went off to the left. And, if you look closely, the last shot blew through the tree.