Ok, I think I'll create both 30mm and 15mm versions. I'll change the description here to advise setting up the constructor to produce ammo output to the ammo box when powered on and the new one will just advise using an HV constructor to make the 15mm ammo.

I have been using exclusively minigun drones for starter bases for all of Alpha 9.2 and never had an issue even with hard difficulty settings unless issues are ones that would stop any turret (Poor line-of-sight, bad terrain, etc). In fact I have had less success with cannon drones effectively taking out drones quickly enough. This is over probably 6 restarts, so it isn't comprehensive, but I do a lot of restarting for testing my own builds :)

For some reason I thought 30mm could be made an a HV constructor but it looks like you're right.

It is possible to load the containers and use the constructor with the control panel and logistics menu even before digging it out and make ammo immediately on power on so that you have ammo before the drones can arrive. I'm just worried that the minigun turrets don't kill the drones before they can get into weapons range but I haven't tested that lately.

I like it, quick critique though: You say make 30mm before powering on but you need a large constructor from a base or CV to make that.

Alternatively you could swap the turrets to Minigun Turrets which take 15mm that can be made in HV/SV Constructors, which would actually allow for making the ammo before powering on. :)