“Death of a Boar” comes from the 1952 edition of an Odhams annual called Summer Pie.
Set in Algeria, a country Canning knew from his war service, it describes a boar-hunting trip on which six people set out, all crack shots. When one bullet kills one of the hunters, and then passes through his body to kill the boar, it is up to the doctor in the party to extract the bullet which will identify the murderer.
I am grateful to Jamie Sturgeon who tracked this one down for me.
Summer Pie, Odhams, 1952