Fusion Torpedoes fire automatically, though all UNSC missile ordinance does not fire against Covenant units unless they are unshielded. In canon, missiles had no effect on shields, only kinetic energy.

The MAC and refit MAC is the difference between a standard MAC and the Autumn's 3-shot MAC.

Nav Buoys grant your ships a speed boost, so if you build a bunch and put them in a line, it will increase the speed at which your ships go from the front of the line to the end. It's very helpful for resource collectors without controllers, and getting your ships somewhere on the map faster if you can't afford a slipspace jump.

Missed ranges, but as far as they go MACs are around 10km and naval guns around 5km.

Thanks for your help. Are the covenant shields similar to a cloaking field from Homeworld 2? Or do I need to remove the shields with a MAC or Naval Gun? I'm guessing the shield is why finding the covenant is difficult, even when using the sensor ping.

Nothing like watching those MAC rounds go downrange. Beautiful work.

I think the shields are essentially deflector shields.