My google-fu was too weak to find a good English reference for this potential, so I'm putting an excerpt from the JP Swiki page.
There is an effect not shown in the in-game potential description. The weapon potency raises along with the amount of the blast gauge (5%/6%/7%).
As for the main effect, once the photon blast is unleashed, you'll gain additional bonus effects, depending on the type of the photon blast unleashed.
- Helix type: +6% potency
- Cetus type: +40% PP recovery speed
- Julius type: reduces damage taken by 15%
- Troy type: -20% PP consumption
- If you equip another mag during a quest and unleashed a different type of photon blast, the bonus effects are cumulative.
- Changing areas will keep the bonus effects.
- The bonus effects are cleared when you return to the gateway ship.
The Redux version has a better potency boost (18%/19%/20%).