Also, you will want to mark your flat as a pistol before acquiring any <16" barrels.
Don't believe any vendors that say "The FA parts are not included in these kits, they were removed by the importer" or "They come with some funky trigger group, we don't know what it is, but it's not the FA parts"
If you believe that, I have some Chinese food w/o MSG to sell you, and maybe a bridge or two.