Don,
that was a cobbled together AR with a few goodies and some not. Depends on what a person wanted. Those short barreled AR's come in 2 flavors. Mid length gas tubes and the carbine length gas tubes. The mid length tubes are easier on everything as they don't accelerate the bolt as quick. That one had a 16" barrel, which is the shortest you can go legally.
he mentioned the bolt and barrel, but didn't say whose upper it was, and whether it was a flat top, probably, whether the the barrel extension had the m4 (iirc) cuts and if the receiver had the appropriate matching cuts. from what I read, the 2 styles are incompatible and need matched accordingly
my hunch is that there was a reason, other than what is going on in the market place. around here AR's have been gone for a couple weeks. one local gunshop had people standing in line 200 deep.
standard offers for a plain jane ar were in the 12 to 1500 dollar range here. a person could walk into a gunstore and walk out with cash. guns with all those goodies could go for 15+
I am just leery or someone who comes onto a sight like BPCR net with very few posts and tries to get rid of a gun like that during a time when people are jumping on them.
and with a trade like that, it would be really difficult to get a person's own gun back if they discovered something was not right.
I could be completely full of it on this one, but..............
I have been watching gunbroker, and people are sort of ignoring some of the more usable rifles, the ones with 20" to 24" barrels that can double as a hunting/varmint rifle, like this one
http://www.gunbroker.com/Auction/ViewIte...=325519086
the search to use is HBAR, "heavy barrel". an A3 upper is the flat top, an A2 upper has the carrying handle attached. 1:8 twist is a bit better than a 1:9, a 1:7 twist barrel is needed to really stabilize the 62 gr or heavier bullets. in the older days, 55 gr were the norm, but as the military realized, anything at a distance needed a heavier, longer bullet (sound familiar) and they started going to heavier projectiles. a chrome lined barrel is better, but not a necessity for someone who keeps their rifles clean
Dave