There are issues though. Skeet guns are 28-34" barrels which is super-long. These guns are also heavy. Once you have ammo loaded up, you're talking 11+ pounds. These guns size and weight make them almost unusable for anything outside of drones. Carrying around an extra gun and heavy ammo is a big commitment both physically and logistically.
But I think an open question is if it could be made portable enough to tote around on the battlefield.
shotgun slugs aren't usable in any serious, consistent way outside of maybe 20 meters (~60 ft). nasty stuff if you're in range, through.
Shotgun slugs can be useful well beyond 20 meters.
https://en.wikipedia.org/wiki/Shotgun_slug#:~:text=A%20slug%....
As a Canadian, I am normally not the one correcting others on the basics of firearms.
If attack drones can move like racing drones, that’s going to be a hard shot to pull off though
The loitering "drop grenades on cars" kind are probably much easier to knock down.
9mm rounds go 1500 ft per second, so probably within 300 meters a drone wouldn't have the reaction time to dodge a bullet with precise aim.
It could also be mounted on a dog, real or robotic.
Actually building this thing though might be a science fiction dream.
About a decade ago, DARPA developed a .50 caliber gun round that has onboard guidance.[1] They were thinking snipers, not anti-drone, but maybe the concept can be adapted.
The concept of tactical air superiority is now questionable. The USAF used to boast that American troops have not had to fight under a hostile sky since 1952. That era seems to be over. There are so many portable systems now that can take out an aircraft.
Jam-resistant drones are already a thing. Drones are going to have to be shot down one at a time. This is quite possible but the missiles to do it can cost more than the drones.
[1] https://www.defensenews.com/air/2024/02/08/us-army-spent-bil...