A neighbour in his 80s lives near a railway line, and frequently is visited by rats. He has one of these, made by Webley, and uses it to great effect just like a sniper rifle out to a range of about 15 yards.
There are two sorts of cartridges for these. The early ones have a small case head and a paper body with a very small charge of shot. However I found some Fiocchi ones for him with a full length brass case and marked "Double Shot" and indeed they have a much heavier charge and are more effective.

I expect I may inherit this in due course - we shall see.

HB