Length and width of hull are the same a chimera, since the bassy uses the chimera chassis. Width does depend somewhat on if you put on the extra armour bits to the sides. Using the blast shield is also optional, and most people seem to go without since it is a pain to transport and IMO looks better without it. From memory, the length of the barrel is probably less than 3" from the hull, maybe 2.5" but 3" should be safe. Unfortunately I no longer possess my IG, having sold them 6 years ago.