For instance, or if you need a discreet solution to shoot at invasive species among other things, without having to rely on the supply chain for ammunition You need air, you need lead. Eventually you can make the projectiles yourself without too much difficulty provided you have the minimum required equipment. Now you need gasoline for the compressor... In order to refill the air canister, that's the main weak point when it comes to it. A/C Compressors are a thing, or this https://www.youtube.com/watch?v=GLioiPfqyMs why not lol... I'm going to look if some guy successfully built the equivalent by making a crossover between a modified paintball and a air carbine... Ideally you want a DIY one... In order to override limitations; imagine the same thing but remote controlled and "belt fed", with even more power... That thing already pierces a cinder block with the full auto mode repeat impacts as you can see...