Mounting turrets onto a vehicle is extremely fun. However, bullets are not always easy to come by. My suggestion is to add a weaker electrically powered crossbow-turret as an alternative.
You still need to load it, it still requires power, and it lacks the range and stopping force of gun-turrets. It also probably won’t be as useful for dealing with metal or chitin coated targets.
In exchange, you get slightly a easier to create turret, that uses a kind of ammunition that even fairly early-game archers can reliably acquire (though they still need to have the knowledge, tools, and skills to make turrets, so it shouldn’t hurt game balance). Also, you get a turret that turns zeds into pincushions, and a use for all the spare crossbows that are so helpfully set up in trap form in fields all across the map.
perhaps have an upgraded XL version that fires specially made “heavy” bolts. essentially an automated ballista. Slow firing, but incredible stopping power.
Is it feasible to build such a thing? I think so. Self-cocking crossbows are a thing, as are magazine fed crossbows. Combine the two, add in the same tech used to automated the other turrets, and you’re done.
