Actually none of the barrels are available right now as reported by more than one person who has called H&R on barrel availability, they were told barrels won't be available until the end of March or April. My best guess is it's an attempt to reduce their inventory levels to a minimum for tax purposes, that's for Remington, Marlin and H&R. Marlin makes H&R's barrels, when I had an H&R contact in December, he could not get a barrel production schedule from Marlin, best he could get was a tentative first quarter 2010 and it looks like it will be the end of the first quarter before any are made.

As for the 45 Colt Carbine, it's listed in the 2010 catalog, so I suspect it will be available as an accessory barrel again......eventually.
Tim