Not a Colt or S&W.
I thought it was an ASTRA but my book THE ILLUSTRATED ENCYCLOPEDIA OF HANDGUNS by A B ZHUK shows, on page 81, it to be an piece of Rohm GmbH junk. A RG-57 to be exact.
You beat me to it.
The cylinder release is the first clue.
The cylinder release, coupled with the shape of the hammer, then the unshrouded base pin... means it’s a Rohm.
It’s a piece of crap. Cheap metal, poorly fitted. It’s a piece of crap, through and through. I’ve seen guys put inordinate amounts of effort into trying to fix Rohm .22LR revolvers.
Personally, I’d rather rub cow patties into my hair before I owned one.