Thanks. I assume the steel tube (16mm OD/8.3mm ID) i have is oversized for .22 builds, right? Maybe I can get a steel tube locally that is okay to use with .22 ammunition but I am not sure about that, other than 304 and 316 steels are hard to get locally.

Thanks for details. I just inspected the documents of Rogue and Rebel. It feels like they require too much work to do without a drill press or a CNC but I have no rush, I can take my time to build something.