Here was my solution. The huge heavy aluminum gun barrel is supposed to be glued into part C18 and then retained by part C19 though how exactly the gun is supposed to stay in elevation and not instantly depress under its own weight is not explained. Also, DO NOT glue the muzzle brake onto the barrel before you pass the barrel through the mantlet cover....for obvious reasons. My solution (after several attempts with counterweights etc ) was to glue the gun in elevation using two part epoxy and then, once the gun housing was fitted to the model glue the mantlet cover to the mantle at the required angle (the front face of the cover needs to be at right angles to the gun tube). All in all, a hideous piece of design so typical of DML's recent products......