The Geissele Super HBAR MOD1 16" Complete Upper Receiver in Distressed Diamond Cut is a heavy‑barrel assembly designed for precision, durability, and heat capacity in 5.56×45mm NATO builds. Its robust .812" gas journal cold hammer forged, chrome‑lined barrel with a 1:7 twist is optimized for stability and long‑range consistency, while the mid‑length gas system and Super Compact gas block help ensure smooth cycling. The free‑float MK16 M‑LOK rail and full Picatinny upper provide a rigid platform for optics and accessories. Finished in DDC and ready for your choice of BCG and charging handle, the 08‑617S is ideal for custom rifles where accuracy and sustained performance matter.