Puting more then one in bone armor would be useless as you gain more in it from bone prison and bone wall.
For each point in Bone Armor you gain 10 Absorb.
While for each point in Bone Wall or Bone Prison you get 15 absorb + you raise the damage of Teeth, Bone Spear and Bone Spirit. So if i puted 19 point more in Bone Armor it would raise only by 190 absorb for making the damage with Bone Spear and Bone Spirit quite shitty.

We aint in 1.09 anymore you do less damage now in duel so barb do not do many thousan per attack anymore. My fireball sorc does 6000 dmg with fireball and i dont kill player in 1 shot. It take 2 or 3 and they dont have max resist. You can always cast Bone Armor again once your hit.


If i remember correctly you only do 10% damage in duel now.

Also DR = Damage Reduce.

Edit:

So 50% DR would actualy make a barb do only 5% of his damage (When it is not blocked by shield)