Help with demo round damage calculation

[Helmholtzz]

This is the tool tip for demo round for my current gear:

 

'Fires a demolition round which explodes on contact dealing 5585-5706 kinetic damage. This damage is increased by 25% if the target is affected by your gravity vortex.'

 

So that means my demo round should do 6981-7132 damage. Taking into account that my surge is 71.85%, if a demo round crits it should do damage in the scale of 11990-12256.

 

Now here is a combat log showing the damage i dealt on the operations training dummy.

As you can see the demo round damage is 4377-4937 for non critical hit. and for critical hits the damage is 8912-9457.

 

I was wondering how much armoring (damage reduction) does the boss have? Does the dr explain the reduced damage for the non critical hits? Also I thought critical hits bypass armor. Does that mean the operations bosses have other damage reduction against kinetic damage? Or am I wrong to believe that critical hits bypass armor?

Edited October 19, 2013 by Helmholtzz