Also check Jim Chambers Flintlocks. They have a .com website that is well worth visiting.
Buying locks direct from them is the best course of action and their rifle/gun kits are superior.

Tip Curtis Frontier Shop is a good place to find barrels and almost any other parts as well. He generally has most Green Mountain stuff in stock and often has barrels TOW and others do not.
P.O. Box 203, Cross Plains, TN 37049, (615) 654-4445.
tipcurtis@bellsouth.net

Dan