My dilemma is I have the MT6400C which I bought during the ban. Now I'm wishing I had a 6920, i.e. "the real deal".
It seems to me the options are:
1. Send it to someone to thread the barrel, install FH, and replace the stock w/collapsible stock.
2. Buy a 6920 upper to replace the original upper, and replace the stock w/collapsible stock.
3. Sell the MT6400C and buy a 6920.
I'd like to hear what you MT6400C owners are doing.