The NAA Mini-Master is a single-action revolver chambered for both .22 LR and .22 WMR, with an included conversion cylinder that lets you swap between the two. At 7.88 inches overall and 10.80 oz, it is larger than a typical NAA mini but still compact enough for pocket or backup carry. 
 

Key Specifications 

• Model Name: MiniMaster 
• Brand: North American Arms (NAA) 
• Caliber: .22 LR / .22 WMR 
• Action: Single Action Only (SAO) 
• Capacity: 5 rounds 
• Barrel Length: 4 inches 
• Overall Length: 7.88 inches 
• Weight: 0.7 lbs (10.80 oz) 
• Sights: Adjustable Marble Arms Front & Rear 
• Grip Type: Finger Grooved Black Rubber 
• Finish: Stainless Steel 
   

Features 

The 4-inch barrel gives the Mini-Master noticeably better velocity and sight radius than the shorter NAA minis. Marble Arms adjustable sights are a real asset at this size; you can dial them in for a specific load rather than accepting a fixed zero. The stainless steel construction resists corrosion and holds up to regular carry. The finger-grooved rubber grip handles recoil from .22 WMR rounds without discomfort during a range session. The SAO mechanism requires a deliberate thumb-cock before each shot, which encourages careful trigger discipline.

Owners of the NAA Mini-Master tend to appreciate the combination of the 4-inch barrel and adjustable sights, noting that accuracy at 15-25 yards is respectable for a rimfire revolver this small. The dual-caliber capability gets mentioned frequently as a practical plus.

The stainless finish and overall build quality receive positive comments. The grip size is a common complaint from shooters with larger hands, who find extended sessions uncomfortable. .22 WMR recoil in a sub-11-oz frame is noticeably snappy, which surprises some first-time users.

Accuracy at close range is generally satisfactory, though long-range comparisons to larger handguns are not really applicable at this size. Holster options are limited given the revolver's unusual proportions, which comes up in discussions fairly often.

Sentiment is balanced: the Mini-Master is valued as a compact revolver with real sighting adjustability, while the small grip and limited capacity are accepted tradeoffs.