Heavy Hitter’s description: “+5% Damage for 7.5s on Heavy Attack Hit. Stacks 5 times.”
However, this talent does not apply to anything but Melee Damage
Even tho Payback Time’s description says: “+20% Damage for 5s after being Hit by a Melee Attack” this Talent does apply to everything, including Ranged Damage
2 Videos that I have uploaded as Supporting Evidence show that Talent doesn’t apply to Bleed and Ranged Damage
Steps to Reproduce (Required):
Play Ogryn
Take Heavy Hitter
Stack 5 stacks
Shoot your Ranged weapon and see that it doesn’t apply
You gain and maintain stacks with heavy attacks, but during the duration of the buff, going by the description you should get a +%damage buff not exclusive to melee. I think the confusion comes from then the implied ability to switch between weapons and thus gaining the damage buff on ranged weapons aswell for the duration of the buff.
Steam guides have been saying that it only counts for melee damage, so it is most likely just a description error.