The main difference is the .22 CB and BB caps and the Short, Long, and Long Rifle bullets are heeled, meaning they narrow behind the bullet bearing surface so the case can be the same diameter as the widest part of the bullet. The .22 Mag and .22 WRF both use a straight sided bullets and the cases goes over them, so the case is wider than the bullet, like with a centerfire straight wall cartridge case, and so the case is wider than the .22 rounds mentioned in the first sentence. A number of revolvers have had conversion cylinders over the years, so the bullet and bore fit are not the issue.
With the mag and WRF cases wider, you need someone with the right chamber reamer to rechamber the barrel for either one. The WRF has a 45 grain lead bullet and is loaded to lower velocities if you are wanting something that's a little less of a jump, but their harder to find. The difference isn't large enough so a firing pin located for the .22 LR would have trouble firing the Magnum or WRF in any instance I'm aware of? The extra four thousandths of radius at the rim, though not a big difference, may make extractor fit too tight in some actions. That could take a bit of attention to sort out, but nothing herculean by way of effort.
Some .22 RF barrels are awfully soft. That and the extra pressure and powder may combine to cause accelerated throat wear if you use it a lot with the magnums. But as a single shot, you probably won't use it that much.
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Last edited by Unclenick; March 28, 2010 at 05:00 PM.