Glad I kept mine !!!! I did so to preserve the technology and perhaps one day see the carbine improved and back in production. Granted, plastic parts suck !!! Early Volunteer carbines did have sand cast aluminum lowers that used greasegun .45 ACP mags. There were also 9x19mm versions using Sten mags. The later plastic lower carbines used Thompson mags and worked well. No drums were ever employed AFAIK. Though some custom adaptions have been made both functional and decorator. These Volunteer carbines used square tube receivers.
Previous Thompson clones such as the Spitfire carbines were open bolt, round tube semi-autos later banned by the Feds. Eagle carbines I believe were grand-fathered as OB semi-auto items. I should check my notes. There is a Spitfire NFA collector-shooter website.
The Manchester Volunteer carbines (and pistols) production ended when Mr Manchester passed away. Revived popularity and current scarcity has driven prices of these "econo-arms" out of sight.
VD in AZ
As simple as they are to make, I would think a revived version would sell well. With HK G3 lowers selling for so cheap nowdays, I would think a tube upper with it's own magwell and the HK lower as the "drop in FCG" you could have a neat little toy. Heck, interchangeable bolt heads and magwells for different calibers would be easy as well.
There is a hazzard of employing imported milsurp parts into any firearms design in that the availability may be cut off and/or pricing driven out of sight by some political thugs or "supply and demand".
These Thompson clones did use milsurp Thompson buttstocks but... those were made and found here in the US. Same deal with the mags used. However WW-II is nearly 70 years ago for much of that inventory.
Modern CNC manufacturing can allow better quality components which these simple pistol-caliber carbines really need.
Parts kits for these carbines and pistols is another idea...
VD in AZ