No it's a custom built SBR (short barreled rifle) which is a NFA item that is regulated by the ATF like suppressors.
I don't use mine for long range it is built for a different purpose. I wouldn't go 20" on one. Although the round is made for a 20-24" barrel the benefits don't outweigh the cons for me. Especially if you hang a suppressor off the end which will be an extra 6-8" so if you run a 20" barrel with it you're looking at 26-28" barrel that's just way to long for me maybe it works for you.
If it were me I'd go 16" barrel with suppressor. 16" will get you out to 500+ yards easy.