I have two SPR type rifles.
Both lowers are Stag with RRA 2-stage trigger and A1 stock from
Moore Militaria.
Uppers are Stag: one is A2, the other is A3. Both uppers have Stag B/BC/CH. These can be bought in combo deals through several vendors.
Both use
White Oak Armament SPR barrel: one is threaded; the other is not.
Adco also carries this barrel. The barrel comes clean, and you will need to have a FSB attached. On both of mine, I use an adjustable/match FSB. When you buy the barrel from either WOA or Adco, I suggest that you have your FSB done then. Both companies do excellent work.
Both use a carbon fiber free float tube: one is a Clark; the other is a Briley. Both are good tubes. The Briley is a slightly larger diameter.
Mine shoot well below MOA and absolutely love Sierra 77 and 80 grain bullets, on just about all powders used: IMR-4895, VV-133, VV-135, and even IMR-4064.
You can have WOA or Adco build one, or you can have the fun of doing it yourself.
I highly recommend both WOA and Adco for top of the line service and work. Both are honorable and trustworthy.
Edited, because I cannot spell
write right the first time.