North American Arms Mini Master, Single Action Only, Revolver, 22LR/22 WMR, 4 Barrel, Stainless Steel, Silver, Rubber Grips, Adjustable Sights, 5 Rounds NAA-MMTC The NAA Mini Revolver 22LR/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.