An interesting and surprisingly little known fact is that Major Boothroyd was a real person and that was his real name.
He wrote Fleming, telling him how much he enjoyed his first Bond novel. He corrected Fleming’s designation of the Beretta as something like 6.75mm, as a .25 was really 6.35. He also told Fleming that a real OO7 would not have used a .25.
It turned out that a friend of Fleming at Holland & Holland had already corrected him on the .25 caliber but had not mentioned the Beretta as unsuitable. Fleming wrote Maj. Boothroyd and asked for a good suggestion of a spy’s gun and the Major wrote him back with the PPK in .32 idea.
To Major Boothroyd’s embarrassment, Fleming described the .32 as “hitting like a brick through a plate glass window.” as of course Boothroyd knew it was no powerhouse.
They became friends and Major Boothroyd said that Fleming, while not knowledgeable on guns was an excellent shot.
There is more to the story but I am tired of typing.
http://en.wikipedia.org/wiki/List_of_James_Bond_firearms
When Ian Fleming wrote the first of the James Bond novels, Casino Royale, he had no idea the direction in which the stories would go, let alone how many he would eventually write. So when he introduced Bond as using a Beretta 418 in a flat chamois leather holster he probably didn’t think too much about it. He had used a .25 ACP Baby Browning during the Second World War when he was in Naval Intelligence and felt it was an appropriate side arm for a secret agent on an undercover mission.
Shortly before the publication of From Russia, with Love in 1956, Fleming received a fan letter from an author and gun collector, Geoffrey Boothroyd. He told Fleming that he admired the Bond novels apart from the hero’s choice of weapon. Boothroyd felt the Beretta 418 was “a lady’s gun” with no real stopping power.[1] He also objected to the choice of holster. Boothroyd proposed that Bond should use a revolver like the Smith & Wesson Centennial Airweight. It had no external hammer, so it would not catch on Bond’s clothes. The Smith & Wesson could be kept in a Berns-Martin triple draw holster held in place with a spring clip which would decrease Bond’s draw time. Boothroyd also said the suppressors Bond occasionally used were rarely silent and actually reduced the gun’s stopping power.
Fleming thanked Boothroyd for his letter and made a few points of his own in his reply. He felt that Bond ought to have an automatic instead of a revolver; perhaps Boothroyd could recommend one? Fleming agreed that the Beretta 418 lacked power, but pointed out that Bond had used more powerful weapons when necessary, such as the Colt Army Special he uses in Moonraker. Fleming also said that he had seen a silenced Sten gun during the war and the weapon had hardly made a whisper.
Unless Fleming was describing a pistol and not a revolver under the dash in Bond’s car in the first and third novels, “Colt Army Special .45” is a misnomer. Colt did produce a double action revolver early in the twentieth century that was given the name “Army Special,” but Colt built that revolver on what it called its .41 caliber frame, first introduced in 1888 as the “New Army and Navy.” Colt released a smokeless powder version in the early 1900s, now called the Army Special, a name Colt continued until it released the Official Police model in the late 1920s, typically chambered in .38 Special or .32-20 Winchester, but never in .45 caliber. That large caliber was restricted to Colt’s New Service, first released in 1905, and the Colt Shooting Master, issued in the 1930s.[1]
Ultimately Boothroyd recommended the Walther PPK 7.65 mm as being the best choice for an automatic of that size, with its ammunition available everywhere. He suggested, however, that 007 ought to have a revolver for long-range work. Fleming asked Boothroyd if he could lend his illustrator Richard Chopping one of his guns to be painted for the cover of From Russia, with Love. Boothroyd lent Chopping a Smith & Wesson .38 revolver that had the trigger guard removed for faster firing.
Fleming had Bond’s Beretta caught in his holster at the end of From Russia, with Love, an event that almost costs the secret agent his life. In the next novel, Dr. No, a Major Boothroyd recommends that Bond switch guns. Major Boothroyd chose the Walther PPK 7.65mm after testing the Walther PPK, the Japanese M-14, the Russian Tokarev, and the Sauer M-38.
Bond is issued a Walther PPK but is told to carry it in a Berns-Martin triple draw holster, which is designed only to carry revolvers. This mistake was possibly due to an error in Fleming’s notes, transposing the Walther PPK for the Smith & Wesson Centennial Airweight. However, Fleming lore says that Fleming had bought such a holster and had it sent to Jamaica, making this error all the more puzzling. It has been argued over the years that Q-branch could have modified this legendary holster to accommodate automatics, but this is unlikely- the design of the holster was centered around the cylinder of a revolver, where the spring clip would “grip” the pistol.