Aero Precision APAR538705M26: The R-ONE handguards are designed with size and weight in mind, while still providing plenty of real-estate to accommodate any attachment needs the end user may have. Aero Precision\'s proprietary ATLAS attachment system is a durable and dependable mounting platform, maintaining a slim profile while still providing the strength and stability customers have grown to love from Aero Precision handguards. This complete upper does not include a BCG or Charging Handle. Includes: M5 Assembled Upper Receiver 15\" ATLAS R-ONE Handguard 18\" .308 SS Barrel, Rifle Length Low Profile Gas Block and Rifle Length Gas Tube Product comes assembled M5 Assembled Upper Features: Forged from 7075 T6 aluminum M4 Feedramps .2795 takedown pin holes Laser engraved T-marks DPMS High Profile (.210) Tang) Includes port door and forward assist ATLAS R-ONE Handguard Features: Full top picatinny rail for optional attachments Quick disconnect sling socket at the 3, 6 and 9 o\'clock positions Compatible with low profile gas blocks 1.5\" Inside diameter 1.75\" Outside diameter Compatible with AR-308 Upper Recievers with a thread pitch of 1-7/16 x 16 along with a DPMS High Profile (.210) Tang Rail 18\" .308 Stainless Steel Barrel Features: Twist: 1 in 10 Threading: 5/8 x 24 Material: 416R Stainless Steel Finish: Bead Blasted Gas Block Journal: .750 Gas System Length: Rifle Length Weight: 51.2 oz DPMS Barrel Extension HP and MPI Tested