What Weaponskill did you use and are you staggering the Weaponskill between classes + have all 8 people in the BR? also how fast are you killing Ogre?
With those numbers i can see under 3min kills being easily possible but i have personally not seen anything close to those kinds of numbers in DH and not since back when my LS was practicing BRs on Uraeus.
I personally want to be proved wrong about BRs because even if i think they are clunky and a terrible design if they can cut time off a clear they are well worth perfecting them.
But so far from testing i have done and videos posted of LS's doing BRs they don't come close to doing that type of damage im not even sure half of that.