There is an active private Facebook group that is run by a group of customers.  Facebook Group

http://www.nmlra.org/nmlra-gunsmithing-seminar -- Information about the annual gunsmithing seminar and workshops held at Western Kentucky University.

http://contemporarymakers.blogspot.com -- A site by Art and Jan Riser which displays work associated with the longrifle culture.  They update the blog on a daily basis and this is a rich resource for the longrifle aficionado.

http://www.longrifle.ws/ -- The website of the Contemporary Longrifle Association

http://nmlra.org/ -- The website of the National Muzzleloading Rifle Association

http://www.muzzleloadermagazine.com/  -- Muzzleloader magazine website.  A great resource for those interested in historical aspects surrounding muzzleloading rifles.

http://www.engraverscafe.com/   -- A high quality discussion forum site dedicated to the art of hand engraving.

http://www.flintriflesmith.com   -- The site of the late Gary Brumfield.  Contains a great deal of information pertaining to the art and history of the longrifle. 

www.ricebarrels.com -- Makers of fine muzzleloading rifle barrels.