Description

The Hydra Quick-Change Upper Receiver Assembly is designed to give users a single upper that can adapt across multiple calibers while keeping operation straightforward and familiar. It’s built on the Hydra Quick Change Barrel Upper Receiver (QCB-D) and configured to support both pistol and rifle cartridges without forcing proprietary or complicated setups.

For pistol calibers, the system operates using a direct blowback design. For rifle calibers, the upper runs a direct-impingement system. Each caliber stays true to what works best for that cartridge rather than forcing a one-size-fits-all solution.

In its all configurations, this complete upper includes a 10.5-inch barrel, a standard flash hider, a bolt carrier group and a charging handle. The result is a compact, reliable setup that drops onto compatible lowers without additional tuning.

Caliber changes are part of the design, not an afterthought. The quick-change system allows users to move between supported calibers efficiently, keeping the upper relevant as needs change over time.

Available Calibers

The Hydra Quick-Change Upper supports the following calibers:

Rifle calibers (Direct Impingement):

• 5.56 NATO

• 300 Blackout

• 7.62×39

Pistol calibers (Direct Blowback):

• 9mm

• 10mm

• .45 ACP

What’s Included

• Hydra Quick-Change Upper Receiver (QCB-D)

• 10.5-inch barrel

• Standard flash hider

• Bolt Carrier Group

• Charging handle

Notes on Configuration

This upper is designed as part of the Hydra modular ecosystem. Caliber changes follow the same quick-change approach used throughout the Hydra system, allowing end users to adapt the platform without specialized tools or permanent modifications. 7.62 x 39 models required to use exclusively the Hydra 15 lower with AK pattern magazine well.