The texture I used for the lightning was a single wobbly line and 3 different noise textures. The line was used as the main part of the lightning and the noises were used for distortion and dissolve.
The lightning was created by distorting the line with two different noise textures. This gave the line a jittery movement that felt like lightning.
I used a Dynamic Parameter to control my lightning in the particle system. The parameter was used to make the lightning travel from bottom of UV to top, to dissolve the lighting, and to create offsets in the different particles.
Most of these things happen fast so it's hard to notice but without them the lightning will feel bland and stale.
It was really fun to try and figure out how the lightning would move across the gun and how the whole sequence would look. A lot of time this project was spent on adjusting values in particle systems so it was really fun trying to get the gun to feel as powerful as possible without overdoing it.