Supposedly Shock 3 does more damage per second but it has less damage per shot.
If you’ve unlocked these weapons in your Guerrilla Facility building you can see all the stats by tapping the “i” info button on each of the buildings.
Also while looking at the info of a defense building (or a sicario), tap the “damage per second” text to see “damage per shot” and “recharge time”. These are very relevant and ignored by a lot of players.