A small question about bone shield I can't seem to get a direct answer to

[Zalsaria 0]

Sorry if its a basic question ahead of time but I looked through the first 5 pages and did not really see anything.

 

I decided to roll DK again since Wrath for Legion and I have a question about blood shield. The tooltip and various people say it loses a charge every hit, my question is, why is it that when say I was doing LBRS dungeon before 60 when I would have an entire room of mobs on me I would expect my bone shield to basically instantly if not in a second or two be removed. However, this never happens I might lose 2-3 stacks per like 10-15 enemies I have on me for sometimes 10-ish seconds, if that is the case does that mean I simply can only lose a charge every certain amount of hits, or am I simply reading the tool tip wrong and that is what it says.
 

[Kharth 9]

I think that it is sort of like how lightning shield used to work. Like it is active and we get the DR but it can only proc a charge every so often. If it lost 1 charge per hit it would be damn near useless on trash packs and hard to keep it up on bosses. I have no simulations or fancy equations to back it up, just the little bit of mythics and invasions I've done in last week or so where 3+ things are hitting me and I have bone shield up enough to even build 5+ charges easily (to use that one talent). 

 

Maybe one of these more experienced DKs could fill us in a little better.

[Avlivar 0]

Bone Shield will apply the damage reduction so long as it's active, and has an internal cool-down of 2 seconds. So being hit constantly with 10 stacks would take 20 seconds for them to all be broken. Because of this, you can keep the buff above 5 stacks at all times fairly easily. I'd advise against taking the talent that allows two charges to be consumed in exchange for more reduction. That can burn through your bone shield fast.

Edited August 24, 2016 by Avlivar

[RyanThomson 0]

The other thing to consider here is that you don't lose a stack if you dodge/parry the attack.