bedbugbilly,... the way I understand it, Pietta's "Shooter's model" has closer tolerances with the cylinder's chambers machined to match the barrel's bore, and maybe some other modifications.
Probably with the extra $700.00 over the standard Pietta, the same improved "modifications" could be done by a competent gunsmith for less money (I dunno).
Hopefully we'll hear from someone who has experience with the "Shooter's Model", chime in with additional details.
Old Iron, I have owned two of Pietta's "Shooters Models" over the last decade or so and they are very accurate. The first one I bought in the early '90s, and though it was the most accurate pistol I have ever fired, including both cap 'n ball and modern cartridge revolvers, had a problem with the cylinder pin not fitting quite right so I sold it about 10 years ago. The second one I bought from Cabelas around 2005 when they still carried them. Very accurate, though for some reason, not quite as accurate as the first one, it uses a .457 ball. Very nicely finished with a silver trigger guard and authentic Remington 1858 stampings on the barrel.
Around a decade ago, I had a top notch cap 'n ball gunsmith (his name now escapes me) do an action job on a late '90s standard Cabelas Pietta 58 Remington, including cutting the forcing cone to 11 degrees and it is almost
as accurate as the Shooters Model. In fact, I like it better and shoot it more often.