Lilja barrels are made from rifle barrel quality, 416-type stainless and 4140-type chrome-moly steels manufactured in the U.S. In addition, all of their tooling is either made in their shop or by U.S. suppliers. The barrels are pull-button rifled, with a very uniform twist rate. Every barrel is stress-relieved in a vacuum furnace, handlapped, and inspected with a video bore scope. Quality is also assured through the use of our Sheffield Air Gauge System and Rockwell Hardness Tester. Stainless steel barrels are guaranteed to be uniform dimensionally to .0001″ and free from internal tool marks. Chrome-moly barrels are uniform to within .0002″ end to end.