I had a Ruger Single Six with two cylinders; one for regular .22s and one for the .22 Magnum. It shot both cartridges equally well.
Some people however, don't understand the difference between the two. I repaired a Marlin Model 39 .22 rifle one time. The guy said he could single load it, but the .22 LRs would not work in the magazine tube. When I got the rifle apart, I found a .22 Magnum round stuck in the tubular magazine. Seems his wife did it? At least that's his story and he's sticking to it.
Navy Vet & SWIFT Boat OIC