Hvy Weapons Engineers is a technology that can be researched at the Research Center in Tech Level 4. It costs 500 Food and 600 Carbon, and gives +1 range and +20% attack vs buildings to Cannons and Hvy Weapons Factory units. Note that the added range does not affect the Pummel and Hvy Pummel. It is available to all civilizations except the Rebel Alliance.
This technology makes it easier to take down enemy structures, and the added range is particularly useful for the Anti-Air Mobile.
"This Tech Level 4 research project grants your Heavy Weapons and Cannons a significant damage bonus against buildings, and greater range. Pummels' range cannot be increased, while the Anti-Air Mobile cannot attack buildings."
—Manual description