Hodgdon does not show data for the .45-60 online, but in a .45-70 30gr of IMR 4198 under a 405 cast gives 1370 fps and 17,000 cup.

FWIW smile

I also used filler when shooting a 500-450 #1 Express years ago, using data that Seyfried had published. 10 grains of Dacron over a fairly hefty amount of H4198. It did shoot to the original fixed sights that way, however.

"...the designer of the .270 Ingwe cartridge!..."