The 77/22 could not be set up as a convertible, the bolt face is recessed to take the 22LR case, and the action is not long enough. Even the 77/22 Mag would be difficult, as it would require extensive modification and a magazine redesign. As far as a convertible 22LR-22Mag goes, Sako made the Quad System, a receiver with interchangeable barrels. The receiver is long enough for 22 Mag and 17 HMR, a flat bolt face, and the 4 interchangeable barrels have the appropriate chamber for 22 Mag, 22LR, 17 HMR and 17 Mach 2. But this is not what the original post asked. He asked if there was a rifle that could fire both the 22LR and 22 WMR. The answer is still the same.