Geoffrey Boothroyd told me that some fans had even suggested arming Bond with cap-and-ball .44 Remingtons! Some of the answers here haven't been much better.
Keep in mind that he has to appear unarmed on most occasions! And the ammo must be available in most countries.
When Fleming referred to a "sawn" barrel, as on the Detective Special that Bond had under hs pillow in, "Casino Royale", he evidently wasn't aware that the guns came from the Colt factory as snubs! He really should have just said, "short" barrel.
Taping the grip safety on the Beretta .25 also wasn't too swift, as the tape would loosen or stretch with time and no longer hold the grip safety all the way down. Nor was the tape in lieu of the grip panels going to make the gun much flatter. (The Beretta was either the Model 318 or 418, not the later M950, which has no grip safety.)
Boothroyd wrote a very good article in "Sports Illustrated" about Bond's guns. It may have been the last gun article that ran in that rag! If memory serves, it was in April or May of 1962 or 1963. Many libraries have back issues, sometimes on film. It's well worth looking for. I think it may have been April 19, 1962.
By the way, when Fleming armed Bond with the Centennial in, "Dr. No", he screwed up. Boothroyd had suggested a S&W M27 .357 for the car gun, and for heavy duty generally, with the Centennial as his "always" gun. He had in mind partly that the .38 ammo would fit either gun. Fleming liked small autos, and went for the PPK. He then confused the two revolvers. This was before he bought his own Centennial.
In "Dr, No", the villain's men were armed with .30 US carbines and what Fleming called "the usual model" of Smith & Wesson .38 revolver. That one is easy to figure out: he meant the M&P/Model 10. In .38/200 caliber, it was a mainstay of British forces during Fleming's war service, and he probably saw many of them. Dr. No probably issued .38 Specials, though. Either Victory Models, or the commerical M10. His base wasn't too far from the US, after all.
Johnny Guest-
You almost never make a mistake, but I read that article in , "The American Rifleman" that Boothroyd sent to Fleming, and the gun you said was a Steyr .32 was actually a Sauer M38. I'm guessing that you just had a momentary synapse lapse...the guns compared in the article were foreign autos that had seen WW II service, compared to the US M1911A-1 .45.
I hope you see this as an observation, not as a criticism.
Lone Star