Zenith ZF5 (with HK fire selector) with SD and K variants made for the tactical horror shooter game SCP: 5K by Affray Interactive.
It also includes the coate folding stock for the K variant, and MLOK handguards from Midwest Industries for the standard and K variants.
Models done in Fusion 360 and Blender, textures done with Substance Painter, renders in Marmoset Toolbag.