I’ve just tested and it seems critical strike chance is calculated incorrectly for Rampage sub skills.
My character has:
5% base crit
+8% from armour affix
+8% from Insatiable
Increased crit sources:
200% from Insatiable
50% from Bush Stalker
150% from Rageborn
50% from blessing
So crit chance for Rampage (and its sub skills such as Storm bolts) should be (5+8+8)*(1+2+0.5+1.5+0.5)=115.5%
Rampage always crits. However, Storm bolts from Crackling Assault node crit very rarely. I tried 100 times and I only saw 26 crits which is close to 5*(1+2+0.5+1.5+0.5)=27.5%. So it seems added crit sources do not actually add - which contradicts at least affix description.