if you read the books he has a storm bolter that he paints green to mimic the bolt pistol that the marine gave him and he lost.(storm bolters are more fun in game also) And the proportions are suposed to fit in with wh40k in heroic scale and alot of the details will be painted on. Thx more comments plz!
Eisenhorn uses a bolt pistol given to him from some space marine.(can't remember who) I'd change the storm bolter you have him useing it's a bit to large for the model. Overall Great effort.
it is nice, but compare the artwork and your version...- the proportion of the plastic material is way to far away from the well done green stuff work...but you should keep on, as the work on the sculpted part seems good!
edgar