I've been working on many of my own turret designs and have often struggled with making the most space-effective design for my builds: The circle. When you make a turret, you have to make room in-house for the widest radial measurement in order for your turret to rotate the full 360. In a square/rectangle turret, that measurement is from corner to corner across the center. But as a result of that, you have lots of space not being used when the turret is in it's resting position. This is just boring, wasteful empty space that could be replaced with armour or weapons, or could be removed entirely to keep your craft more diminutive.
The circle, however, has the same radius throughout. When you build a housing for a circular turret, you can stay completely flush to your turret and not worry about jamming.
Here's a square in a square. The inner one with the diagonal line represents the turret in the housing.
The diagonal is the same length as the length between inner sides of the turret housing. That's the largest possible square turret you can make in a square housing. You can certainly fill in the corners, but at rest there is a large gap between the turret and the housing.
And now the circle.
Here, we don't have that issue!
Now you're wondering "How do we make a circle with square parts?" Well, you don't. However, there is a template I used to use in my Minecraft days that does the job extremely well.
https://www.minecraftcirclegenerator.com
You go down to the "Circle Generator", check off the square marked "Centered" if you want your radius offset by one (You probably do, we pretty much all center our builds off the middle of a middle block) then enter your radius. It will generate a circle for you to build out of squares, and you can go from there!
I have found this template incredibly useful in my builds. From turrets, to radar dishes, to cool looking missile batteries. Enjoy!
