Years ago, Colt brought out a cute little rifle called, if memory serves, the "Colteer", or some such. Anyway, it was a singlw shot that you could get either in .22LR or .22WRM. I bought one in .22LR that spit gas in my face every time I shot the rifle. Turns out it had the bore for the .22LR and was chambered for the .22 WMR. This was back in about 1958-9 as I recall. The case would split at the rim. I took it back for a refund and did not get another as a replacement.
Paul B.