If you don't consider your time as valuable, your cost assessment is correct. If you enjoy casting lead, that's a different story. It's your time and your hobby do as you wish, but your case is not for most of us. Slugs cost twice as much as pellets.
My time is valuable, so I spend it in a way to that gives me some amount of pleasure. As for my time having actual cash value, hah, good luck convincing the tax man, they think it is worthless. I totally agree with your argument about commercial slugs, unless you need the terminal ballistics, slugs don't make too much sense cost wise.
But for me, the cast slugs
are a better value, since I can't get paid for my time these days. I've got about 15 lbs of lead right now, so that's what? I figure that's over 3100 slugs that I can cast.
I enjoy making things, casting is just part of it. I enjoy designing stuff and making it, be it via machining, printing, or welding. Nothing gives me more satisfaction than using things I've made. So casting my own slugs and shooting them in an airgun I modified to my liking, yeah that gives me pleasure.
Using a Doppler chrony that I made from scratch, that gives me pleasure too. I designed the circuits, simulated and tested them, did the systems analysis and loss budget, selected a capable platform, wrote the signal processing code and stuffed it all in a printed box. Works well enough for my use case. Unfortunately, I was nearly complete, when the FX chrony came out, so my dreams of fielding a low cost rig died. Couldn't see a viable commercial path for me, with their head start. I know what it takes to get radar systems approved, and commercialized, I did it professionaly. Been to official test labs in the US and China for world wide type certification. No matter, I got a heck of a lot of pleasure figuring out the puzzle and doing it myself.
