Straightline - thanks for added pictures A shot from the top of the front sight would add to the info. Does the brake backend hole appear to be enlarged? The stub looks larger diameter than a standard bbl stub (7 3/8" bbl), and set back slightly. Possibly necessary if bbl was used to center work? Jim, your thought? Highly doubtful to be factory or even a "lunchbucket/Givernment" job. Interesting modification by someone with time or money to ?waste?, but sure ain't the first or last one.

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TOMBECK