see thread here
https://rcwarshipcombat.com/threads/3d-printed-cannons-1u-twins-0-5u-twins-1u-single.446264/
3d printed Cannons: 1U twins, 0.5U twins, 1U single 1.0
half unit twins for Duca, one unit twins for Provence, gas cores
half unit twins for Duca, one unit twins for Provence, gas cores