BerdanIII
10-18-2008, 02:20 PM
Just got back from the annual Shilen Barrels Open House / Swap Meet.
I took the plant tour and was amazed. Barrel (round) stock is received and analyzed to make sure it meets specifications and is cut to length and given an initial heat treatment in big electric kilns (How would you like your toast?). The bore is drilled on WWII-era Pratt and Whitney machines with carbide cutters made in-house. After ensuring the barrel is straight (crooked barrels are tossed; Shilen doesn't straighten barrels) it is reamed with reamers that are also made in-house. It was weird watching the reamer work. The free end of the barrel was wobbling all over the place while the chucked end was still. The guide (an employee) said the reamer just follows the hole made by the boring machine. Rifling is by the pull-button method and takes about 30 seconds a barrel. The buttons are made in-house, too. Stainless barrels are hand-lapped to remove the lubricant used in the rifling process and then both stainless and chrome-moly barrels are sent back to the kiln for stress relief. After that, they're done. After looking down the bore of a finished barrel with a bore scope and looking at the barrels in the sale rack, I realized that all my barrels are about as smooth as the inside of a cast iron sewer pipe.
All-in-all the best field trip since I went to a steel mill in Junior High.
I took the plant tour and was amazed. Barrel (round) stock is received and analyzed to make sure it meets specifications and is cut to length and given an initial heat treatment in big electric kilns (How would you like your toast?). The bore is drilled on WWII-era Pratt and Whitney machines with carbide cutters made in-house. After ensuring the barrel is straight (crooked barrels are tossed; Shilen doesn't straighten barrels) it is reamed with reamers that are also made in-house. It was weird watching the reamer work. The free end of the barrel was wobbling all over the place while the chucked end was still. The guide (an employee) said the reamer just follows the hole made by the boring machine. Rifling is by the pull-button method and takes about 30 seconds a barrel. The buttons are made in-house, too. Stainless barrels are hand-lapped to remove the lubricant used in the rifling process and then both stainless and chrome-moly barrels are sent back to the kiln for stress relief. After that, they're done. After looking down the bore of a finished barrel with a bore scope and looking at the barrels in the sale rack, I realized that all my barrels are about as smooth as the inside of a cast iron sewer pipe.
All-in-all the best field trip since I went to a steel mill in Junior High.