Farm nova blasters from uc shipyard then sell em to buy xray visor,its the easiest way of gttin xray visor,one of my frnd did runs on numa for about 8-9hrs a day,he did that for about a month still no drop.
My tip if u do numa or delta=)dont open chests(i have seen lots of vanity drops,most of em were from mob n 1-2 from guardian) good luck :-)