Man.. i have not even been able to play yet but already knew how this worked! Use one consumable and kill the Ultra.. if you don't get a drop, use one again and the percentage will be higher for a drop to happen. Rinse and repeat as much as you want until you get the drops you want. ONE AT A TIME! Stacking 5-10 or whatever does not increase the chance on that run! It has the same effect as using just one coin! Don't waste them people! Edit - after using around 70 three of coins one by one , I have now got all of the new guns. Missing just the heavy year 2 weapons. Done well with armour to although had the Stag and Alpha Lupi 4x each!!! I am getting an engram drop around 5-8 goes each time.