by Tom Gaylord
Copyright PyramydAir.com ©2009. All Rights Reserved.
This is a common problem with first-time owners of breakbarrel guns. In my experience, they always say the barrel closed accidentally until you press them. Then they admit they pulled the trigger with the barrel broken open "to see what would happen."
When the barrel snaps back closed with several hundred pounds of force, it bends at the weakest point. The result is always the same--a barrel bent upward at some point near where it enters the baseblock. Often, the wooden stock will be cracked at the same time, but that's not as predictable as the bending of the barrel.
While an airgun barrel may be made of steel, it 's quite soft. There's usually no hardening of the metal beyond the random work-hardening that results from manufacture. A strong person can actually bend the barrel in his hands, perhaps using his knee or chest as a fulcrum.
At the Roanoke Airgun Expo in November 2002, a dealer bought a Beeman R1 that had the classic bend in the barrel. He bought it for a song, so he wasn't too concerned that it needed a little work, but he gave me permission to photograph the barrel.
For perspective, I laid a straight brass tube along the cocking link under the mainspring cylinder. That tube is close to parallel with the mainspring tube, making it easy to see the bent barrel.
This is a classic bent barrel resulting from firing the gun with the barrel open. It takes only one time to do this, and it happens almost every time.
Some airguns have anti-beartrap mechanisms that prevent shooting the gun until the barrel is fully closed. This also prevents personal injury when fingers are trapped in the closing breech joint.
Fortunately, it's easy to straighten a bent barrel. The best method involves a fixture that allows the precise application of controlled pressure, but barrels have been straightened using picnic tables as the only tool. The job is done while peering through the barrel to watch for the formation of concentric shadows.