Abstract: This invention relates to an improved lock for revolver cylinders of the type that releasably locks the latter against rotation by passing a rod from the barrel into one of its chambers, such improvement being characterized by a loose-fitting lock rod of a length greater than that of the cylinder but shorter than the combined lengths of the latter and the barrel, a friction-held keeper for insertion into the barrel ahead of the lock rod for the purpose of keeping it in place, and an extractor capable of being connected to the keeper upon insertion into the barrel for purposes of retrieving it preparatory to removing the lock rod. The extractor includes as a part thereof a normally recessed indicator attached to the front end of a probe which projects out the rear end and through an axial opening in the keeper to where it engages the front end of the lock rod so as to extend the indicator and thus provide the user with visual confirmation that the lock rod is fully seated in the cylinder.