Just in case anyone needs an great barrel for that carbine project. I happened to see this:
http://www.brownells.com/rifle-part...s-prod54526.aspx?psize=96&avs|Make_3=AR-15/M4
Wylde Chamber, 1:7 Twist - I run an 18" on mine and LOVE it! $269
http://www.brownells.com/rifle-part...s-prod54526.aspx?psize=96&avs|Make_3=AR-15/M4
Wylde Chamber, 1:7 Twist - I run an 18" on mine and LOVE it! $269