*Fix For Packing Heat Achievement Glitched May 2015
I unlocked this achievement today by fully upgrading the exotic shotgun Lord of Wolves from the House of Wolves DLC.
I had been unable to unlock this achievement since i started playing this game two months ago.
I fully upgraded 14 different non-DLC exotics without the achievement unlocking.
I am confident that the only way to unlock this achievement at this time is to fully upgrade 1 of the 4 House of Wolves DLC exotic weapons.
The 4 House of Wolves exotic weapons are:
347 Vesta Dynasty, Lord of Wolves, Queenbreakers’ Bow and Dreg’s Promise.
A house of wolves exotic weapon can be obtained via the Elder Cipher Exotic Bounty, randomly dropped only in level 34 & 35 by the Prison of Elders final boss.
The only other way to get this achievement at this time is to fully upgrade the Vex Mythoclast. This weapon can only
be obtained by killing Atheon in the Vault of Glass on hard mode.