Bleed has a max stack of 16 and ticks for 20 damage per tick at max stacks vs unarmored enemies, there is a nicely curved ramp of damage per tick based on number of stacks and bleeding has, as all other attacks, different damage multipliers depending on target armor type.
Bleeding stacks work like other DoTs now - Stacks will tick damage while reducing the number of stacks over time until all stacks run out and the DoT ends. A single stack of bleed ticks damage every 0.5s and has a duration of 1.5, so should tick on average 3 times.
Will take a look at the bleed stacks applied by Ogryns Bull Gore - it was not tweaked this time around, might be a bit low but then again you can hit like 100 guys with it so the total stacks up.