Steve Tasitritsis' 'ATLAS ARMS', 2704 N Central, Chicago and (later) 7952 Waukegan Rd. Niles, Illinois offered replacement barrels for Smith and Parker guns in the 50s and 60s using tubes made by E.S.C. Vickers (England) and fit and finished by Armaf in Belgium
http://www.littlegun.be/arme%20belge/artisans%20identifies%20a/a%20armaf%20fr.htmThese Parker barrels have a 1954 date code

A Smith recently turned up with barrels by Armi Sarezzo in Italy.
I believe Dewey Vicknair uses PacNor barrels
www.VicknairRestorations.com