When you say normal airguns do you mean lower caliber ones or just basic airguns designed for pellets only?
If it's just for personal use then the video below might be of some help.
If I were to do it myself then I would do it like a self rolled cigarette. A filter to push the shot through the barrel, shot instead of tobacco and paper to hold it all together.
If I wanted to be a bit more professional I'd try to find a drinking straw (plastic if you can still find them where you live) that fits perfectly in the barrel.
If it was plastic you could use some heat to make it malleable and push it over a .25 cal sizing rod so it would fit perfectly in the barrel.
You basically just need 3 things. Something to push the shot, this can be plastic, wood, foam. The gauge shot you want to use and finally something to hold it all together, be it paper, plastic. I think some sort of paper would be best, perhaps the papers for cigarettes would work as they are rather thin but this in turn means it might break easily.
There are some products on the market you might take inspiration from.
View attachment 462068View attachment 462069 Shot shells for airguns have been around for years, mostly for .50 caliber airguns afaik. I have seen several different versions, from shells to wads you fill with your shot of choice.
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