Geissele showed their 10.3" Upper Receiver Group during SOFIC.
http://soldiersystems.net/2018/05/22/sofic-18-geissele-automatics-10-3-urg/
The commercial version with 16" barrel is available and you can pre-order it from Brownells
https://www.brownells.com/rifle-parts/receiver-parts/receivers/upper-receivers/ar-15-usasoc-upper-receiver-group-improved-urgi-5-56-m-lok-prod114412.aspx
MrGunsnGear recently posted a short video of the URG
From: Soldier Systems Daily, MrGunsnGear