The Buffalo Bore Ammunition 21D/20 is a highly effective 10mm ammunition with tactical grading. Conforming to Saami specifications, it ensures safety during usage with all 10mm pistols. The unique design of this long, lightweight, all-copper bullet results in powder capacity restrictions. However, with Buffalo Bore\'s commitment to quality and detailed testing, the previously noticed reduction in velocity compared to ballistic chart listings (1350fps) is no longer observable. Their \'real-world\' tests confirm a level of performance that adheres to the expectations set by theoretical data.