Typical Jeffery.

Welcome to the NE.com!

I just got a .577 2 3/4" express and followed in the footsteps of many.

A time honored formula is 40% weight of black in IMR4198.

1 drams = 27.3 grains, then 27.3gr * 6.5dr * .4 = 71 grains of IMR4198.

With foam of felt as fillers.

This is a starting load. Increase/decrease by one grain at a time until it regulates.