I know when you normally unlock weapon slots as answered in this question, but mine's a little different. I have a few characters that have already beaten the entire game, or almost the entire game (right before the end of the final mission). If I create a new character, is there any way to unlock all his weapon slots without playing through to the point at which he gets all four weapon slots?
I ask this because I have a character that I've done this for, but I'm not positive how. It might have been because I was farming the Warrior and this character finished that mission, but I'm not sure.
edit: Character A has finished the game on Normal and TVHM, and is on the very last mission right before calling the moonshot on UVHM. Character B is a newly created character. I started the game in UVHM with Character A, brought in Character B to call the moonshot, then saved on Character B. I think that's why all the weapon slots are unlocked on Character B, but I'm not positive.