I'm thinking of making a cheap Reece concept carbine. Use a 6721 and get a FF tube, match trigger, and a A2 stock. What kind of accuracy do you get out of yours? How about prolonged fire? I have a 6520 that holds fine until you get a few mags through it...then it starts to string the groups out after the barrel gets hot. Thanks for any help.
Honestly, it doesn't sound like a great idea.
My 6721 will do 1 1/2 to 2 1/2 inches @100yds. Same lower, same ammo with a Schillen stainless will do 3/4 in. That is what a RECCE is all about.
Without the barrel, it's just a look-alike. Better to develop two uppers, use the 6721 for aggressive carbine use, and slowly build an upper around a quality match quality barrel. Start with one of the great barrels, Lilja, Douglas, Krieger, then add a FF tube, upper receiver, etc one piece at a time.
BTW, a non-FF stainless match barrel will outshoot a FF rack grade 6721, hands down. Put your money where it actually does some good.