Recognizable Features

Identifying guns is a bit like learning a language. Once you understand enough different words, you become able to decipher the meanings of brand new ones by breaking down the syllables, figuring out their basic meanings, and then reconstructing the word. Well, once you’ve seen enough guns you start to be able to recognize characteristics and features to the point that you can make pretty good educated guesses about the lineage of weapons you may never have laid eyes on before.

Some of these characteristics are basic mechanical features, like open-bottomed magazine housing indicating Mannlicher-type clip use (Carcano, Dutch Mannlicher, Berthier, Steyr-Mannlicher, etc). Others are semifunctional design decisions, like the open-topped slides used on Beretta pistols for decades (models 1915/19/23, 1934/35,  1951, Cheetah, 92/96, and more). And some are fully aesthetic elements that a particular nation or factory has decided to keep around. A good example of that is the distinctive beer-keg charging handle used on Swiss rifles for about 70 years, from the Model 1889 to the StG57:

Swiss StG57 rifle Swiss Model 1889 rifle Swiss ZfK55 sniper rifle Swiss Bern experimental assault rifle

In fact, it was that charging handle that clued me in to the identity of that Bern prototype the first time I saw it…