I have a national match flat top upper on my franken-15 it is scary accurate and works extremely well on the Bushmaster/JP Systems/RRA lower. Best group so far 3/4" at 200 yards and totaly reliable. My SAKO varmiter 22-250 is getting jealous because it has become my go to gun for Coyotes.
I got my FFL scouring the net, and stores for an AR-180B. I just hope I don't fall victim to the broken hinge blues, but I just did not like any of the competitors, exept for the Bushy M-17S, but they don't make it anymore. I read abds things about the Bushy's trigger, but the one owner I talked to face to face swore by his rifle.
If you are looking for a 180B try Total Firearms in Mason, MI they had one when I was in there a week or so ago, asking somewhere around 700.00 I believe. If you google Toatal FireArms in MI, thier site should come up. Lol, has my pic on it for winning the S&W M&P they were giving away.