Looking at some old manuals where data are listed for both AA-1600 and W-680, it seems like they are not identical. The Winchester powder seems to provide better velocity in most of the cartridges where both are listed, although the Accurate version often has greater charge weights.
So, it is not certain exactly how the particular lot of powder that you have will perform. You will need to try it to find out.
While it is probably too slow to be enjoyable in a revolver, it MIGHT be useful in a cabine.
QuickLOAD says a case full of 1680 gives a 300 grain XTP about 1378 fps from a 20" barrel, with about 30,000 psi peak pressure and 75% of the powder burned. For comparison, a case full of H-110 is predicted to give 1584 fps with a peak pressure of about 38,000 psi and 95% of the powder burned. Dialing back the H-110 load to the SAAMI max pressure (36,000 psi)still gives 1562 fps with about 94% of the powder burned. So, clearly QuickLOAD thinks that the 1680 is to slow to be optimum for this application.
There is a 400 grain LFN bullet in the QuickLOAD database that I am not familiar with. Loading a case full of 1680 under that will exceed the SAAMI pressure limit by a lot, and it gets the % burn up into the 90s. Reduciing the charge to get the pressure down to SAAMI limits still leaves the burn rate at 90%.
So, going to a very heavy bullet MIGHT get you decent INTERIOR ballistics in a carbine. BUT, it is not clear that the longer bullet would stabilize in the twist rate used in .44 Mag carbine barrels, so your EXTERIOR ballisics might not be acceptable.