Hellblaster Volleygun: another nasty war machine on the side of the Empire

The lethal creation of the deranged Imperial Engineer von Meinkopt, this weapons terrifying reputation has since spread to all corners of the Old World. Its nine separate barrels are divided into three "decks" and are turned by means of a central crank, firing around three shots per deck which would shatter the enemy in hail of miniature cannonballs.^[1a] Helblaster crews may choose to fire all three decks in quick succession, or to load and fire the decks one after another. Either method has advantages.^[2a]

Even heavily armoured Chaos Warriors can be torn to shreds by a single volley, though with such devastating power comes a greater risk to the artillery crew. Helblaster Volley Guns are notoriously prone to sudden, cataclysmic explosions. As a result, those crewmen who operate a machine that is so prone to catastrophically blowing them up, tend to be paired up with the priests of Morr. (SOURCE)

Here a small selection of the official editions:

I have opted for a darker colour scheme and I am pretty happy with the 3x3x3 solution I have found for the main structure. The three triggers will soon follow in the next version, given that dragon plumes are the only and pretty expensive option. Unfortunately, they are not available in any metal color.

Proportions are once again perfect and "happening" quite spontaneously. There is some magic in it.

Might also try and see to extend the bar underneath along the axis of the machine and re-work the back-side with additional cogs and gears. Or elevate the guns from the wheels and distance them a bit more.