Hmmm... the no voids in the frame seem to indicate a lower value arm. Shape of the "ring" - "loop" atop the frame suggests mounting for a fixed barrel - suggesting a blow back action and so a minor calibered arm. The notch in the 'loop' seems it might be a void to clear an extractor. (it could be an indexing notch, too.) The shape of the trigger guard with hook puts me in mind of something I cannot bring to mind.
Allow me to ask where it was found, and general circumstances? Oh, is it magnetic?
Allow me to ask where it was found, and general circumstances? Oh, is it magnetic?