North American Arms Mini Revolver, Single Action Only, Revolver, 22 WMR, 1.625 Barrel, Stainless Steel, Silver, Rubber Grips, Fixed Sights, 5 Rounds NAA-22MS-GRC The NAA Mini Revolver 22WMR is the most popular Mini-Revolver ever produced. With the many current accessories, it is versatile for many applications and is the standard by which other Mini-Revolvers are judged. This model fires 22 WMR ammunition, and comes with rubber grips.