With the drop of 8th edition the dual twin autocannon loadout for dreadnoughts has been very popular and for good reason. I've had two dreadnoughts for quite some time that came in the Assault on Black Reach set from a few editions ago. Decided to do a little cutting and scratch building to achieve the appearance of twin autocannons.First I used a hotwire cutter to remove the previous weapon loadout on both arms. Using some round sprue from Malifuax models and a bit of brass tube and we're done.
Here you can see a side by side comparison of the original and the converted model.
All in all a very simple conversion and doesn't take all that long.