So out of 10 cases i opened 3 bronze, 5 iron, and 2 lead (what is really good, cuz often its just lead)… it seems like i found a trick/maybe just luck.
I won’t tell you how yet, but it seems like there is smth, i have to test it more 
I was buying cases 1 buy 1 and opening, (was trying to trade up br-16 for arty- neded those leads)
anyway i got a tip it has to do smth with the skip button
Try it.


