Xenonauts already reduces some of the micro through the auto-selling of excess alien items.
I would suggest to make the clips / magazines of all firearms available in unlimited quantity.
The only things the player would manufacture would be the "heavy" ordnance like launcher rockets, grenades, and interceptor missiles.
Things that come as single items.
Constantly monitoring the number of pistol and rifle clips is just no fun.
That also prevents the sadface when an entire clip is "used up" even though only a single round had been fired in the mission.
Tracking the actual number of bullets is a silly level of detail that doesn't fit with the rest of Xenonauts.