I had to go and look at that Bearcat after seeing what WMG said he paid for one..... The GB explanation sorta cleared it up for me:
"Manufactured in 1994, this new model Blue Super Bearcat has a four-inch barrel, fixed sights, smooth rosewood grips with silver eagle medallion, original interchangeable .22 LR and .22 WMR cylinders, and the transfer bar hammer-block safety. There is no "Ruger New Bearcat" rollmark on the left side of the cylinder/grip frame. About 1,000 convertible Bearcats were made, and the magnum cylinders were reported to have been returned. A "timing" problem made them unsafe and therefore the magnum cylinders were recalled. Samples with both .22LR and .22 WMR are rare. The magnum cylinders should not be used. As stated on the Ruger website: Firing a magnum cartridge in a cylnider not correctly timed with the barrel may result in excessively high pressures, causing the cartridge case head to fail, possibly resulting in personal injury. The Bearcat convertibles were shipped in yellow and black hinged boxes."
You learn something every day.........
J.