Q: I own a Winchester 1890 in .22 Winchester Rimfire and a Model 62 in .22 Long Rifle. Will a .22 LR fit in the WRF chamber and fire without danger to the firearm and user?
A: With few exceptions, it is generally never advisable to attempt to chamber or fire any sort of cartridge other than that for which the firearm is designed and hopefully for which it is marked or otherwise indicated. The exceptions typically include those situations involving a “family” of cartridges, usually straight-walled and headspacing on a rim, where the difference between cartridges is primarily only a matter of case length. It is usually acceptable to fire the shorter cartridge in the chamber for the longer sibling. Examples would include: .38 Spl. in a .357 Mag.; .44 Spl. in a .44 Mag.; .32 S&W in a .32 S&W Long; .45 Colt in a .460 S&W Mag.; .22 WRF in a .22 WMR; and .22 Short and Long in the .22 Long Rifle.
In the case of .22 LR and .22 WRF, the dimensional differences include not only case length but both rim and case body diameter. The .22 LR cartridges will fit loosely in the .22 WRF chamber and rim recess, but they will usually be held at the rim so that attempting to fire the round will usually be successful. Because the small case is largely unsupported, however, it will expand within the limits of the larger chamber, usually splitting from end to end, releasing gas and byproducts of ignition by any avenue available within the firearm, potentially causing harm to the shooter, bystanders and perhaps the gun itself. Removal of the split case from the chamber can also prove to be problematic.
—John W. Treakle, Contributing Editor
