in [...urret-updated__/prototypes/technology-turret-upgrade.lua:157] is this:
table.insert(data.raw.technology["laser-turret-speed-1"].effects,{type = "gun-speed", ammo_category = "railgun",modifier = 0.1})
After I changed as you said, there was a new error:
mod load err:Error in assignID:ammo-category with name 'railgun' does not exist.
Source:at-beam-mk1(electric-turret)