"Best described by Ian McCollum (aka Gun Jesus) as a "Full Auto Flashbang Dispenser".

HK51 is an unofficial Heckler & Koch firearm that was designed by an American gunsmith Bill Fleming, by utilising existing G3 and HK91 parts. It's invention was in direct response to the British SAS and SBS Special Forces request for a compact "Sub-Machine Gun" sized firearm that can still fire the full powered cartridge. Although it did saw very limited service and adopted as the MC51 (Machine Carbine 51), the firearm was very quickly replaced by the HK53 due to the sheer amount of concussion and muzzle blast it produces. The HK51 still sees itself as a fun range toy by many gun enthusiasts. Clone version are also currently being produced by PTR Industries under the name "PTR 91 PDWR"
In a nutshell it's a cutdown G3, or in the otherway around a dummy T H I C C MP5.

Other Attachments: X-Products Drum Magazine, MFI HK Optic Rail, SureFire 628 Pressure + Switch Flashlight handguard.

Production Period: 20th Oct 2024 - 3rd Nov 2024

Modelled in Blender, Textured in Substance Painter

Tris:
Gun + 20 rnd Mag + Optic Rail - 51,072
SureFire 628 Handguard Flashlight - 5,264
50 rnd Drum Mag - 7,584

Artstaton: https://www.artstation.com/artwork/NqaZAq"