They (the Pacific Zephyr's) were quality and nicely finished, but priced pretty high for what they were: An updated Hopkins and Allen underhammer. Like the H&A's of the 1960s, 70s, and 80s, the action was a hammer, trigger, and a trigger guard that serves as a mainspring. What made the Zephyr's special was the barrels with Forsyth (or Forsythe) rifling. Renner had a webpage for underhammer enthusiasts that hasn't been updated. I believe his operation ended up with The Gun Works in Oregon, which still has a website, but doesn't show that particular underhammer design.
If you really want a rifle of that design, just go to Pecatonica River Muzzleloading. They offer (or used to) a couple of underhammer kits, to include the H&A design. Rice Barrel Company offers their outstanding barrels with Forsyth rifling; get one that's tapered or swamped and it would be a lot easier than putting together a Lancaster or Hawken.
