What hand gun did Ian Fleming arm James Bond with in his first five novels?

The James Bond series focuses on a fictional British Secret Service agent created in 1953 by writer Ian Fleming, who featured him in twelve novels and two short-story collections.

For the first five novels, Fleming armed Bond with a Beretta 418 until he received a letter from a thirty-one-year-old Bond enthusiast and gun expert, Geoffrey Boothroyd, criticising Fleming's choice of firearm for Bond, calling it "a lady's gun – and not a very nice lady at that!" Boothroyd suggested that Bond should swap his Beretta for a Walther PPK 7.65mm and this exchange of arms made it to Dr. No. Boothroyd also gave Fleming advice on the Berns-Martin triple draw shoulder holster and a number of the weapons used by SMERSH and other villains. In thanks, Fleming gave the MI6 Armourer in his novels the name Major Boothroyd and, in Dr. No, M introduces him to Bond as "the greatest small-arms expert in the world". Bond also used a variety of rifles, including the Savage Model 99 in "For Your Eyes Only" and a Winchester .308 target rifle in "The Living Daylights". Other handguns used by Bond in the Fleming books included the Colt Detective Special and a long-barrelled Colt .45 Army Special.