Daniel Defense MK18 Painted Low-poly 3D model is available on CGTrader for $60. Original author: Raider3DWeapons. Specs: 67719 polys, 39227 verts.
MAX (Autodesk 3ds Max, filesize: 36.2 MB), OBJ (OBJ, filesize: 2.25 MB), FBX (Autodesk FBX, filesize: 7.3 MB), MAX (Autodesk 3ds Max, filesize: 36.2 MB), TBSCENE (Marmoset Toolbag, filesize: 23.7 MB)