I just bought me a Winchester Model 1886. I will change it to 45-90 Wcf and I wonder if anyone can help with some information on loads for a 405 gn bullets. It is intended for Brown Bear and Moose.

I'd keep it a 45-70 and use Reloader-7 with Remington 405 grain jacketed bullets at moderate pressures. The '90 won't be anymore lethal.

Ralph is right. When you change from 45-70 to 45-anything else, You might as well figure on mortgaging the house to feed that puppy.

45-70 to 45-90?? You will gain nothing, balistically, by doing so. If you use the original barrel you will damage the value of the rifle. At leas get a Green mountain barrel and start form scratch. Brass will cost a bunch more. You will have more headaches finding accurate loads.