The U.S. company Sightmark, which specializes in target optics, is expanding its Mini Shot product family with the M-Spec M2 and M-Spec M3 Solar models, two completely enclosed reflex sights that, in addition to a traditional button cell power supply, can also be powered by a solar panel. We fitted the larger of the two sights on a Glock 21 Gen5 MOS and tested it extensively for you. You can find …