I have read on several threads about not being able to find ammo. Well I just mail order mine because of the non-common varieties I use as well as the common ones. Best pricing I have found for 45-70, 44-40, 45LC, 44mag, and 22LR. I would love to know of other options.
45/70, 44-40 and 45LC are all suitable for lead alloy bullets. Consider hand loading with commercially cast lead alloy bullets. You can hand load 44 Magnum with commercially cast lead alloy bullets too, but only to .44 Special velocity.
You can cast lead alloy bullets yourself. I used to do a lot of bullet casting when I was much younger, however it is hard to resist the next "essential" piece of casting equipment and I think I spent much more casting my own than I would have spent buying commercially cast lead alloy bullets.
I used to cast 650 grain lead alloy bullets in caliber .50 Alaskan. Boy, will those lower the level of hot lead in an electrically heated casting pot fast!
I cast a great number of lead alloy .38 specials, mostly 158 - 200 grains, .44 Russian, .45 ACP, .32 auto, 45/70 mostly 404 grains, .375 Winchester full pressure, 6.5 Swedish low velocity, 7.5 French MAS low velocity, 7.5 mm Swiss low velocity, among others.
High quality Linotype used to be available in 40 pound blocks, cast to fit inside a US Post Office Flat Rate Box, so shipping was almost nothing per pound. Well, that is gone. It was nice while it lasted, probably a decade.