Yavian sniper tower

Yavian Sniper Towers (also Sharpshooters) were weapons developed by Yavian warlords on the planet Yavia. The towers fired electrically accelerated supersonic projectiles at enemies. Occasionally, these projectiles were composed of toxic, radioactive or explosive material.

Sniper towers were highly effective against many of the large animals that were used by the Yavian warlords to attack strongholds. They saw use on other worlds, notably Geonosis, where they were used to defend against Merdeths. They were cheaper than energy based weapons such as turbolasers, but their firepower was inferior, and so they were rarely used by foreign armies.

Technology
The towers worked by generating a strong electric field that would cause metallic bolts to accelerate down the barrel of the gun.

They worked in a similar fashion to projectile rifles.