Reading material

Hi all.... im new to this forum so bare with me if i do some noob stuff...

Ok im a huge fan of warhammer 40k (hope that some of you know it) i really enjoy all that grim and gory future where the worst is always around the corner, the problem is that the target of BL publishing is young kids so the grim and gore stuff has its limits.

I was wondering if any of you could give me some directions to authors / editors / publishers / whatever reading material that fits in that grim, dark and gory future.
Like rated r sci-fi??? i dont know if that exists....

Thanks in advance
I can't really think of much that is gruesome, at least in intent. Maybe some of C.J.Cheryh's works are a bit like that. The Aveti stories are about a different mentality humans have to work alongside and the conflicts of mind and purpose, violent episodes, but not gruesome like Warhammer 50k.

I did like the Last Chance Legion stories in that universe, but there are close to pulp really. A bit like the Aliens vs Predator series of novels out there, only a bit better written!