Here is a modular set of weapons I've prepared for Sword Of Damocles mod I've published for Arma 3 couple months ago.
The set consists of 6 different weapons and a set of 6 attachments and 3 different magazines. All has been implemented into the game with baked lighting due to make up for old non-PBR Arma engine.
I'm quite happy with how complex the weapons are, yet still fit in with the 40k lore. Given very little reference pictures were created I had to got inspired with modern weapons, mostly L85 and TAR-21 assault rifles. The Ion rifle took a couple tries to get right but I'm also satisfied with the result.