This is the 8 Pounder - an 8 shot Gatling, crank mechanism, shotgun with 22 shell magazine. It's also equipped with a shot dispersal attachment. It's quite front heavy so a neck sling is necessary to hold the barrels up while cranking.
It was modeled in 3DS Max 2017 and rendered with the ART renderer and physical materials. It was textured with Substance Painter. The exported metal/roughness textures (4k) worked perfectly with the physical material shader.
I had a hard time with the strap, I had never modeled a gravity dependent object like that before. I must have had 10 goes at it - finally, for the sake of completion (and sanity), went with the last attempt. It was modeled with the side views (mistake on my part) so I had to leave it out of the frontal views. I obviously need more practice with slings!
Thanks for looking!