What kind of gun does General Zaroff use to hunt?

From the text:

"I suggest to one of them that we go hunting. I give him a supply of food and an excellent hunting knife. I give him three hours' start. I am to follow, armed only with a pistol of the smallest caliber and range. If my quarry eludes me for three whole days, he wins the game. If I find him "--the general smiled--" he loses."