First thing you need to do is get the Lyman Shotshell Reloading Book... and read it. Not much radical has changed in shotshell reloading except most loads now use the one piece plastic wads and the hulls are plastic as well. .410 hulls are a bit harder to find as they are not shot as much as 12 ga. Check with a skeet club. You are correct that your cost will be less than 12 ga, but your savings will be almost exclusively in powder and shot. The primer costs the same, and the wad will be the same (or a bit more since they are not sold in the same volumes as 12's). The guys I know reloading the .410 all use MEC machines, either the single stage or the Grabber.