Going back to the 1940's I think it would be common that it was referred to in the old 32.20. In this case we need to remember that we are filtering 65 year old information through 21st century knowledge. There was a day when you didn't just refer to a .22 rimfire as a 22. It was a .22 short, long, long rifle, etc. Today we have added the magnum, and we have a whole slew of centerfire .22. However, for some reason we only view a .22 rimfire as either .22 or .22 magnum, and many people assume that is it.