That's impossible right now, konami configurate the "random" system to open packs, nobody know this, but that's the reason F2P players can't reach easily the "x3" UR cards in 200 pack box like was in the past
Each pack's chance of drawing a UR is 10/600 = 1.6%. Times 30 is 48%. There's not even a 50% chance that you'll draw a UR in 30 packs yet you say it's "rigged" because you didn't draw one?
your maths is wrong for each pack You open the chance of getting a UR increases as the number of cards available decreases so the chance to get a UR will increase with each pack you are going to open. In your calculation You assumed the number of cards stays 600 which is not true.