Kalmah's tunning

It's different for every album. I think Swamplord is half-step down, and the rest get lower and lower, with 12 Gauge ending in two whole-steps down.

This is just my guess based on the sound, so don't quote me =P
 
swamplord half step
they will return half step
swampsong full step (d standard)
the black waltz full step
for the revolution 1.5 steps down
12 gauge 1.5 steps down