Ah yes, the EMP Handgun, or EMP Handgun model 09 as the original work was titled, which you can see more details in the Artstation page of it:
https://www.artstation.com/artwork/aR53Aq

Although the model itself didn't have the additional parts like the magazines and stuff fully modeled, but still.

Gmod version:
https://steamcommunity.com/sharedfiles/filedetails/?id=2797176072

Includes:
sketchfab\kjloyh\skf_kjloyh_emp_handgun.mdl

Credits :
Robert Ryminiecki - Original designer of the weapon.
Valery Kharitonov (@KJLOYH) - Original creator of the model.
NeoLin - Porting to Source.
And PBR Converter by Fennecai ( https://linktr.ee/Fennecai )

Feel free to support the Lambda Group for more addons.👌
https://ko-fi.com/neolin7812
https://www.paypal.com/paypalme/NeoLin7812