I have only seen one XP model and it was in .454, stainless, setup as a scout model with the rear sight removed and the rail mount and a scope installed. Nice looking rifle but not my cup of tea.
I have the .44Mag, 20" Octagon barrel, case hardened receiver. Very nice rifle...too nice for a truck gun so I just bought another from Bud's Gun Shop. This one is a 16" carbine in .44Mag, blued, with a round barrel. I plan on getting a Marble's Tang sight for the 20", nice thing is that that model comes pre drilled and tapped for a tang sight.
No pic of the 16" because I haven't received it yet.