How far back do you want to go?
I'd recommend reading some of the older shooting books. Elmer Keith's "Sixguns", for example. It also helps to remember that the market after the Second World War was flooded with military surplus. This happened after the First World War, but not to anything like the degree of the Second conflict.
Having said that, my thumbnail would be as follows:
1900-1915:
Rifle - 1895 Winchester.
Shotgun - Parker double.
Pistol - Colt M1903.
Comments - The new bolt-action rifles were just becoming popular. Most firearms were hunting oriented, personal defense was not a high priority. Having said that, the new self-loading pistols were becoming quite popular. Remember that men's pockets were bigger in those days, a M1903 or small-framed revolver would fit perfectly.
1920-1940:
Rifle - M1903 Springfield
Shotgun - M97 Winchester
Pistol - S&W K-frame.
Comments - After the Great War, bolt-action rifles became the standard for hunting. Pump shotguns started displacing doubles. Personal defense remained a relatively low priority, but this was the great age of the double-action revolver. Concealed carry became both illegal and uncommon in the 1930s, so the pocket pistols faded.
1950-1975:
Rifle - Sporterized M1903 Springfield or '98 Mauser
Shotgun - Remington 870
Pistol - Colt Python
Comments - After the Second World War, the commercial markets were flooded with war surplus. Converting military rifles to a hunting configuration became a sizeable part of the gunsmithing business. Personal defense still a limited priority, but more powerful cartridges such as the .357 Magnum and .44 Magnum are developed. The former, in particular, finds a home in many police holsters. There's also a great deal of interest in muzzle-loading arms in this period.
1975-1990:
Rifle - M1A
Shotgun - Remington 1100
Pistol - Colt 1911
Comments - There is a MAJOR change in the firearm culture in the 1970s. Personal defense displaces hunting as the primary purpose for firearm ownership. That fact was NOT recognized by the firearms industry, and even took the NRA leadership by surprise. There's a lot of interest in defensive shooting matches, but it's not big money yet. Jeff Cooper has a very, very strong influence on this era.
1990-2005:
Rifle - AR-15
Shotgun - Benelli
Pistol - Colt 1911
Comments - The AR-15 begins to really displace the .30 rifles in this era. Also, red dot sights such the Aimpoint start to replace iron sights on AR type rifles. The market shifts strongly toward personal defense, but the industry does not pick up on the fact. Shooting instruction becomes a significant industry. Standards of pistol marksmanship start deteriorating.
2005-present:
Rifle - AR-15
Shotgun - Saiga
Pistol - Glock 19
Comments - Industry finally realizes the shift in interest by the market. Polymer-framed striker-fired pistols displace the 1911, 9mm displaces .45 ACP. Shotguns generally fade, replaced by carbines. Standards of rifle accuracy improve, those of pistol accuracy deteriorate. Standards of marksmanship follow suit.