I would much appreciate it if you’d keep me in the loop on those future drum mags! :-)
Will do. As far as the 100-round dual-drum M16-type, the Korean Victor brand seems like a good deal at about $140, considering the Beta brand can sometimes hit $270.
Just remember how expensive "cheap" magazines were once, and could become again. I'm already reading "legal scholars" who say the Second Amendment only protects guns as they existed on the day of ratification, and nothing else.
New modes of "speech" are, however, always protected, except when they're not.