I am level 41 Ranger CAST with a gun that hits 360. Does anyone have a list of Guns that I should hunt for and where to find? I rember in PSU it was TWIN GUILD MILLAS+99. Is their an ultimate Rifle to hunt for???

Right now, not really.

Your next upgrade after level 40 should be a weapon from the Photon Booster exchange. Shop area, second floor, far left.

After that is pretty much 400 Unique Badges for a 13* of your choice.

Grind up events and get yourself those photon spheres and boosters I myself was sty k but just hit lvl51 lastnight and picked up an 11* rifle from the exchange I'm not hitting 2k-2.5k per hit jumped from a measly 1.1k to that lol was using red rifle before hand.