just opened 5x T4 boxs all green and blue minus the 1 purple (Flash gren)
I have gotten all the lock box tiers and got my purple Lmg out of a lvl 2
Tier 4 has a much better chance of getting epics and a slightly increased chance of getting legendaries.
Thanks
Sledgehammer
I dunno about this. I had the same idea, but on my first tier 4 box, I got an orange weapon. I've never gotten one from a tier 3.