I have a used black preproduction CTR stock for mil-spec tube. IT has some scracthes; $50; I also have two speedlock systems chrome silicon carbine springs. These were a bit too strong and would not cycle with my MGI buffer; $25 for both. I used them for less than 40 rds. These are not the newer flat wound springs. Email me if interested.
CTR is SPF. Springs still avail.