I've heard this. Is it true that any splash damage counts as grenade damage, for skills like Steady?
The Notes section of the Steady Wiki article mention something like it:
As with Axton's other skills and class mods that boost "grenade damage", Steady will boost the bonus explosive damage dealt by Torgue gyrojet projectiles.
And the Unkempt Harold counting as grenade damage implicates further. I think the Unkempt Harold's projectiles aren't gyrojet.
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Basically, Torgue guns and guns with Torgue barrels calculate two instances of damage: Impact and Explosion, using Bullet and Grenade damage respectively.