I didnt have direct show last time I went there.
I dont know what you use but some nice sounds there
If it doesnt take much time to do why not try a nice rail hum sound and the fire sound. Both the default ones on oa dont work well. Firstly the default sound is just a drone and very difficult to locate positioning due to the poor harmonics. Since the rail gun is lethal it's very important to hear where the enemy is (and not fall asleep with a drone sound).