I had an idea for Railgun. So there is an alteration for striker called Remote rocket explosives which its explanation is "Rockets will explode upon double-pressing fire button" which make the striker become "smart", per se, what if the railgun had an alt that would make it "smart". Here are the specs, please excuse my noobness:
Railgun Alt M3
Unlocked at Brigadier for 125k
Allow player to hold to fire when he/she wants.
Hold fire button, rail fire delay is the same, but when firing delay is finished the player can continue to hold button, till he/she is ready.