G'day agent00.
There were two .461 Gibbs cartridges, coincidentally named the Number 1 (2 11/32 inch long) and the Number 2 (2 3/4 inch long), and each had two loads. The No.1 was more popular for match shooting, whereas the No.2 was slightly more powerful and more popular for hunting.

.461 Gibbs No.1 loaded a 540gr bullet over 75gr BP or a 360gr hollow-nose bullet over 90gr powder.

.461 Gibbs No.2 loaded a 570gr bullet over 90gr powder or a 360gr bullet over 100gr powder.

What exactly do you want to know?