BM-21 Grad PBR Low-poly 3D model is available on CGTrader for $39. Original author: djkorg. Specs: 86000 polys, 1 verts.
MAX (Autodesk 3ds Max, filesize: 6.99 MB), OBJ (OBJ, filesize: 1.49 MB), FBX (Autodesk FBX, filesize: 6.96 MB), TEXTURES (Textures, filesize: 1.56 GB)