grayfox,
I've tested a couple of Montana rifles, and also have one rifle, a 7x57 with a Montana 1999 action and Montana barrel, stocked by what was then Serengeti Rifles and is now Kilimanjaro Rifles. It shoots well, but like some others have encountered, isn't the lightest rifle in the world, despite the 21-inch barrel mimicking the Model 70 Featherweight contour. It's not heavy, by any means, weighing 8 pounds on the nose with a 4x33 Leupold M8 in Talley Lightweight rings, but not exactly a featherweight, either.
I have one of the initial actions in stainless, also barreled with a Montana barrel and stocked by Serengeti in their Leopard pattern stock. Mine is a .358 Win and it has shot 3 shot groups down to .608, outside edge to outside edge of black smudge around holes. Which when you subtract the bullet diameter, is pretty darn good. Mine also has a 21-inch barrel, but has a .650 diameter at the muzzle. To lighten it up a bit, I also bought a MacMillan Edge stock for it. (The Serengeti is awful pretty to bang up, too.) I have a 2-8X silver Leupold compact on it.
