Okay, i've done it! I completed Joe Must Die and ran NG+ back to the end while hoarding supplies to make the Jack fight at the end much easier.
Link:
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This save has the Dual AMG's and Spirit Blade along with plenty of first aids and bombs. Just beat Jack and the trophy should pop.
Again, feel free to add this to your save-set RageSoul51.
EDIT: I wasn't going to upload the save until i'd completed all of the challenges for infinite ammo. I did the first 5 before realising it was going to be too time consuming and most people would rather have the save now, rather than later.