Several options for 922r , CC ti US mag tube, US follower, US Stock, US hand guards, 3 US FCG parts, US trigger housing. If you use the collapsible C stock, and 7rd tube. You have to replace 4 parts and no paperwork required. 922r it’s self is subjective to debate. I’ve saw several conflicting ATF “interpretations” so I guess it applies to whichever letter you follow. As for 922r parts , when replacing parts make sure they are as good or better than you are replacing. the Carrier comp Titanium tube and supplied follower is GTG, the FFT hand guards are acceptable with a little fitting, the aluminum trigger housing is a good option as well. I avoided swapping FCG parts because I’ve heard if issues with some of those. Regardless how ever you choose to approach it there’s an option.