Check out Medieval cannon Low-poly 3D model 4 3D model on CGTrader for $6. High-quality mesh by PhilipStorm: 10471 polys, 10618 vertices.
BLEND (Blender, filesize: 2.27 MB), OBJ (OBJ, filesize: 1.41 MB), FBX (Autodesk FBX, filesize: 522 KB), C4D (Cinema 4D, filesize: 1.04 MB), ABC (Alembic, filesize: 943 KB), DAE (Collada, filesize: 2.37 MB), UNITYPACKAGE (Unity 3D, filesize: 394 KB), STL (Stereolithography, filesize: 1.01 MB)