Hello everyone.

Im Snake Stranski a Perth WA (Australia) based GM looking to run a warhammer 40K RP. but i want to use the classes from Deathwatch, Only War, Rogue Trader and Dark Heresy but im not sure which Core book to use as the "Rules" bible...

Any Advice would be awesome

It's difficult to cross platform all the system. Power levels are so very wonky. From what I understand for combat Only War is a good way to go. But you'll have to balance the power levels either on your own or look at the various threads. Some people have made a unified WH40K system, so you could look at those too.

Thanks for the info. I noticed the disparity in levels looking at Rogue trader ~ Dark heresy