Well right up front, I am holstering a .44 RUGER Redhawk, but feel that my info will make an easy cross to the .45.
#1, I have seen issues with the Blackhawk when I was working with the 300+ grain bullets, in damage to the cylindar pin and the spring loaded cross pin. NEVER saw this happen with the 240 - 260gr slugs.
So first off if I were again to go to a blackhawk and the heavier slugs, I'd look into buying the aftermarket pins to hopefully prevent such damage.
Then, let me address bullet profile. I have yet to take a critter with my Redhawk or even the Blackhawks so I will address profile as it applies to cast bullets in my 45/70.
The WFN or LFN (Wide Flat Nose or Long Flat Nose) bullets are totally awesome in their game taking ability. Do a search for in the field results with these bullets and you will find account after account of just how well these bullets proform on game animals.
The mold I currently use for almost all of my .44 shooting is an LBT/LFN, 310gr bullet.
Not to bad mouth the Blackhawk, they are what they are, a good solid gun, and have been there and done that 2 or 3 times including one scoped "Hunter" model.
But the .44 Redhawk simply handles a steady diet of the 310s at about 1300fps from a 5.5" barrel, with zero issues. No slouch load here.
If I were to look for a new mold, I'd do the need research to assure that stability is possible from a shorter/lighter WFN bullet then the 310gr and hopefully come in somewhere about 270 - 280grs. if possible.
I am just so impressed with the WFN bullet profile that if at all possible I'd hope to stay with that.
But considering the biggest and heaviest critter I am likely to face with my handgun is a Moose, the 310gr .44 while doing a great job is in truth a bit more then will ever be needed.
So as this pertains to the .45, frankly for day to day use on about anything you are likely to ever face, the much heavier bullets are simply not needed and use up lots more lead per shot with no noticable improvement in game taking ability.
They do however, with any powder charge worthy of such a heavy bullet, cause a lot more recoil!!!!!!!!
Keep em coming!
Crusty Deary Ol'Coot