The bottom one is a 9.5" barrel, 1:8 twist, 300 whisper with an AAC cyclone-k suppressor.
I got it from MartyTW at
http://www.teppojutsu.com/
It has pistol gas system. You can see the hole in the handguard to access the PRI adjustable gas block, hidden under there. There is no gas tube in the front sight base.
She runs great with subs or supers. Over all weapon length with suppressor is less than standard 16" carbine.