The problem with it is turret's range. Should be able to defend spawn from DSR, but will then deny huge area of the map from moving.
Constant smoke over the spawn might help with that. Or dynamic walls.
Turrets should be sinlgeshot.
Indeed, the protection of the spawn shouldn't cover a too large chunk of the map.
Well, it could be one or more turret, inside a building that have four entrance or more.
You could still ambush some doors, but not all doors. On the other hand, if you enter, you would be blasted by turrets. If the spawn point is outside, you could use fix smoke.
On the other hand, if players stays too long in the building/spawn area, the turret might get broken (or attack the players inside) or the smoke vanish. If enemies shouldn't campspawn, the players spawned shouldn't camp here either.
I don't care it is single/burst shoot. The point isn't for helping the players to defend the building, but to prevent the spawn point for being a deathtrap for newly spawned players.