@animeaddictionIV and
@jreadingmanga I looked back at the site and notice that I wrote the measure wrong, it said 100-yard gun, my mistake I'm not used to using English distance scales, so I confused the yard with ft
But just to make my point:
"Rifled slug barrels are providing hunters the ability to consistently and accurately hit targets ethically out to 150 yards or more. Rifled barrels come interchangeably with pump and semi-auto shotguns."
"To increase accuracy, scopes and chokes can be used in tandem to create more consistency. Slug guns have notoriety for churning through scopes, though."
"If you know you want to use a slug gun for tight cover, then pick a scope with less power. If sitting over a late-season food plot, a 4X to 12X scope is more than sufficient" (I guess the MC Remington 870 has the latter)
All quoted from the site itself
The site: https://www.realtree.com/deer-hunting/articles/deer-hunting-with-a-slug-gun
So I'm not saying it's better or anything, I'm more like saying people already answered that, it exists, it works, and there are now shotguns already being sold with the necessary stuff for a long-range shot without really needing any further modding, and according to the site it's easier to use
P.S: About him using the scope, I would say he probably shoots from longer ranges but due to the bear being about to kill a child he had to get its attention by firing closer to it, and after that with the wolves he just used the gun he had with him, that happened to have a scope