Simple crafting glitch to ensure you get your desired roll.
When you find any gear it will have 3 status bonuses. Greens will have no mods, blue will have one and purple will have two.
Equally blue will have a lvl 1 mod, and purple will have a lvl 1 and a lvl 2 mod.
Legendaries obviously have a lvl 2 and a lvl 3 mod so that is the only way to get 2 level 3 mods on one item.
So your goal from crafting is obviously to have a purple weapon with the correct passive stat boosts and 1 perk you desire to keep and you will roll the other perk in to your desired tier 3 perk (assuming you dont want a t2 one instead?).
So anyways down to the meat of the crafting glitch. Its really simple. Find the one item you want to have the t2 perk you want, make sure it is either green or blue. Then simply upgrade its level to purple. When you do this it will give you a selection of 3 mods to imbue the item with. If your desired mod is available just pick that and your done. If not? Quit out of the game. Rejoin and retry. It will randomly generate another 3 perks to choose from. Yes its annoying and time consuming but its way better than the cost and difficulty of just fishing for it without this method.
Also I hear disabling directx11 or something will make booting less ahhh... crashy.