as far as I know they use an old Akai MPC60 12bit sampler.
It sounds to me
that they mainly use "acoustic drums" samples (as opposed to electronic, say like the
classic 808, 909 etc)..the gritty-nes it's probably a mixture of old samples, 12bit
sampler and maybe some processing..
anyway you should be able to achieve that with a
thoughtful use of a bitreducer and some distortion-providing machine (if you're in the box
Soundtoys's Decimator is really good at this)
Hope this helps,