Which snake is more poisonous a cobra or a rattle snake?

by my research the copper head it is said to be more poisonous if it bites deep into your skin

I don't know where the above respondent did the "research" but this is not true, as far as humans are concerned the venom is very similar but the the rattlesnake gets the edge because of its larger venom glands and fangs!

The copperhead of North America is less venomous than the rattlers, but the snake called "copperhead" of Australia is more toxic than rattlesnakes.