45-60 Winchester BUT the Danish really sounds right to me

and folks will fuss, but I use Rem 45-70 brass for my Danish

https://www.midwayusa.com/product/860270...-nose-box-of-20

https://www.buffaloarms.com/11-7x51r-danish-loaded-black-powder-ammunition-box-of-20-amo11751rb

Whatever it is, I would use lead bullets and not jacketed.