NARAKA: BLADEPOINT

I obtained this by entering a solo casual mode game vs easy difficulty bots and finding a ballista. The ballistae are marked on the on the map and the symbol is similar to a bow and arrow.

Some of the ballistae are high up, so present a good vantage point, as well as the required 50km distance to unlock the achievement. The ballista I used was in a tower that had a good view of the battlefield. Furthermore, the bots tend to gravitate toward the player meaning that you can wait around if there is no-one nearby. Once some bots begin to move toward you, you can try to pick one off as they approach or are engaged in fights with other bots. Addtionally, the ballista fires an explosive bolt which offers some leniency if you struggle with your aim!

This will also unlock you the ''Super Weaponry'' achievement that requires you to kill an enemy with a ballista :)