Bone Crusher Bow - what is extra blunt damage?

[Brown Radagast]

Is it just +1 blunt, or is it 1d8? Hate to invest in one of these and find out the extra damage isn't all that good!

[Luna]

Brown.. that means it counts as bludgeoning damage on the base damage as well as piercing.
It's mainly to bypass creatures DR.

So it works on skeletons for example since it also does bludgeoning damage.

With a normal bow skeletons would get 5 DR.