A positive view of the widespread private ownership of firearms is closely associated with a mode of life characterized by widely separated owner-occupied single-family dwellings, easy access to wilderness areas, and a well-developed "do it yourself" culture when it comes to such things as home repair and automotive maintenance. In other words, it correlates with such things as the availability of places to shoot, hunting (whether for food, sport, or pest control), familiarity with a wide variety of machines, and a low ratio of peace officers to space. At the same time, a negative view of widespread private ownership of firearms corresponds to life in more densely populated places, where most animals encountered are pets, people hire professionals to change their oil and fix their hot water heaters, and setting up a target range in the back yard will result in complaints from neighbors and visits from the police.
So, a world in which more people participated in (or, at least, approved of) the widespread private ownership of firearms would be one in which more people lived in small towns and rural areas, and fewer lived in cities or suburbs. Making that happen requires the adoption of US-style patterns of land ownership. At the very least, this would require the adoption of US-style laws with respect to land ownership. In many places, it would also require the sort of land reform that took place in Estonia in 1919, that is, the break up of large estates into smaller farms, or "homestead" laws that gave individuals title to wilderness land that they staked out and improved.
Another factor that would foster this lifestyle would be the widespread use of private automobiles. This would support "gun-friendly" rural culture in a wide number of ways, from promoting familiarity with mechanical things to facilitating a "widely-separated single-family home" lifestyle.