Dane,
I have forgotten the dimensions but I know that they will be making more. Give Jason or Liston a call at (828)628-3627. They will give you the skinny on the dimensions and when they will be making another batch.
Also, Ed Rayl will make one to your spec's for about the same price as Rice's 46". I had Ed make a 46.5" X .54 cal that is 1.20" at the breech, quick taper to 1" @ 6" from the breech, 825 in the mid section, .875 at the muzzle. The profile is from an original VA rifle owned by Reaves Gohering. 7 furrows with radius rifling. Neat looking barrel for an early rifle.
Dennis