Watched the 1st half of the video, impressive.
An FN 5.7 pistol, the CMMG FN mag lower, & a Fold AR upper w/ a custom bbl & CMMG bolt would make quite the $3500 carry pair.
@Jeffb1911
Even if you're not getting rifle like permanent cavities from the pistol, you're likely getting them from the 16" and you're getting a substantial crush wound from the tumbling out of the pistol.
And every reload is 20 rounds, fits pistol or rifle.
I'll have to continue to make do w/ my 26 & my 5.56 Fold AR for the time being.