Yes, the main reason was economy. Not only because the case could last for anywhere between 20 and 50 shots, or even more, but because boxer primers were cheaper (1000 boxers cost about as much as 300 berdan, or 'gevelot', as they're known in Russia). Improvised wadding could be used, and loading half-charges was also easier - but both only with black powder. Getting all-brass shells to work with smokeless powder isn't easy.

Ideed, a chapter about ammo could be a useful addition - but I'm concerned about length. On the concept stage, I was thinking 60,000 words, now I wonder if I can fit it in 100,000.

Russian Hunting Shotguns