I don't have a GP100, but love my Super Redhawk (which uses the same action). It's accurate and hell for stout.
Unless you're totally wed to a double action, you might want to consider a .357 Blackhawk. They don't work well for concealed carry, but I personally find them more fun to shoot than any of my double action revolvers. Easier to clean too.
Unless you're totally wed to a double action, you might want to consider a .357 Blackhawk. They don't work well for concealed carry, but I personally find them more fun to shoot than any of my double action revolvers. Easier to clean too.