Hyperion repeater pistols are very accurate but they have the feature of "reverse recoil": the longer the accuracy increases the longer the trigger is held. The listed accuracy on the weapon is what is achievable after the sustained fire increases their accuracy to maximum.
The Leverage uses the long high-power, high-accuracy barrel, resulting in a potent long-range pistol with a low fire rate but high damage, coupled to the standard Hyperion medium-high-capacity magazine. While unlikely to challenge an Iron in terms of raw power, a Leverage can lay down shots for far longer.
Notes
The variants of Leverages in Borderlands: The Pre-Sequel commonly spawns with Hyperion's new-style materials and prefixes which are the same as in Borderlands 2.