Yes that would be the buffer tube.
If you’re looking for an adapter for a standard AR-15, check out the Sylvan Arms side-folding buffer adapter(not sure of the exact name). I put one on my AR pistol and it works great. Easy to install, not sure if O.P. Carries it but they’re relatively easy to find and cost less than $150.
If it has buffer tube threads than yes!
The Matador Arms The Sidewinder Buffer Tube will work with the POF PSG22.
The Matador Arms The Sidewinder Buffer Tube attaches to firearms that use a buffer tube or has a buffer tube attachment. The Matador Arms The Sidewinder Buffer Tube will not fit a MINI Jack AK Pistol.
Yes you can, this is not for an AR-15.
Yes, it would work for your application.
You will need to confirm place of manufacture with the vendor: info@matadorarms.com
According to the manufacturer: "Aluminum and Steel design provides ultra-strong lockup."
This is not meant to be used with any buffer spring. This is not meant for AR15s.