What its max in dr % ? 50-51?

50%

But when it comes to CB [Crushing blow DMG] 100%

Explain that CB plz

Crushing blow count as a separate dmg, Its not same as flat Physical DMG
Dealing normally in PvP 10% of Your / Player "Total Currently Health"

It can be neglected up to 100% making u totally immun to CB DMG

LINK: https://www.theamazonbasin.com/wiki/index.php/Crushing_Blow

Lets say u got 5000 HP ( with zero DR%)

And i got my lvl 9 smiter , shitty random gear , my smite dmg do 2 physical dmg on u

[Your totalt health: 4998]

But i got an item granting me CB (Crushing Blow) , lets just say 70% for the argument,

And it trigger aswell when i made my first hit
(CB always does 10% of ur Total Current Health)
i would do 499 DMG ( just from CB)

+ The 2 i =501 totalt dmg


-----------
If u had
Lets say 50 DR% with 5000 HP

My 2 physical dmg will be lowered by 50% = i only do 1 dmg physically on u

it would also lower the CB Dmg aswell to 249 dmg [CB] +1 = total dmg 250

-------------

If u had
Lets say 75 DR% with 5000 HP

it would lower CB dmg by 75%

BUT Physical DMG by 50% since thats the cap. the extra 25%
will not have any effect on lowering my physical dmg on u

I still end up doing 1 physical dmg

but my CB dmg will be lowered by 75% 124 dmg

My total dmg 125

----------
If u had 90 DR%

CB DMG would be 49,

With 100% DR = nullify CB completely

best