Matt . . No, the box in the picture is one I picked up a few years back. . I have a box and a half of old original black powder Winchester cartridges. . Some of these were handed down. . What I do have is 100 brand new brass cases and a set of RCBS loading dies 45-90. . A friend, here on CGN, casted me up some 300 gr. bullets, so I'm good to go with the new cases. . Also have an old Lyman reloading manual that has all the data, black powder and smokeless, for these old time cartridges with both cast and jacketed bullets. . I also load for 33 WCF, using this manual. . 338 WM 200 gr. bullets work. . I use the round nose bullets and make the tops flat.
As far as seating depth, I believe, the 45-70, 405 gr bullet is 7/32" deeper than the 45-90, 300 gr bullet. . Both 45-70 and 45-90 are suggested to be slightly compressed loads when using FFg black powder (70 gr and 90 gr). . They claimed it burns cleaner.
Here's an example of maximum loadings for both 45-70 and 45-90. . This is way more than I'd ever load for my old time rifles, but just to show what these old girls were capable of in their day.
45-70 . . 300 gr. max. for jacketed bullet 30.6 gr 2400 @1905 fps.
45-90 . . 300 gr. max for jacketed bullet 57.0 gr 4198 @ 2215 fps.
45-70 . . 405 gr. max for jacketed bullet 36.0 gr 4198 @ 1417 fps.
45-90 . . 405 gr. max for jacketed bullet 60.0 gr 3031 @ 1950 fps.
The 45-70 handles the 405 gr. bullet better as the 45-90 has a slower rifling twist to help prevent excessive leading and barrel fouling with the higher speed express loadings of the 300 gr bullet. .