The Smith & Wesson Model 640 is a compact double-action-only revolver chambered in .357 Magnum and .38 S&W Special +P. It holds 5 rounds and has a 2.125-inch barrel. Overall length is 6.6 inches and empty weight is 22.1 oz. The frame and finish are satin stainless steel. Sights are black blade front and fixed rear. 
 

Key Specifications 

• SKU: 163690 
• Model: Model 640 
• Caliber: .357 Magnum / .38 S&W Special +P 
• Capacity: 5 rounds 
• Barrel Length: 2.125 inches (5.4 cm) 
• Overall Length: 6.6 inches (16.8 cm) 
• Weight: 22.1 oz (626.5 g) 
• Sights: Black Blade Front / Fixed Rear 
• Action Type: Double Action Only (DAO) 
• Frame Material: Stainless Steel 
• Finish: Satin Stainless 
   

Detailed Features 

The double-action-only design eliminates the external hammer, which reduces snag points during a draw from concealment. The stainless steel frame resists corrosion well for daily carry. Accepting both .357 Magnum and .38 Special +P gives flexibility in load selection. The ergonomic synthetic grip provides a consistent hold for the compact frame.

The Model 640 DAO draws consistent praise as a carry revolver, with the hammerless design and stainless construction being the most-cited practical advantages.

The snagless DAO profile is the primary reason most users choose the 640 over the single/double-action Model 60. For pocket carry or holsters with tight retention, the absence of a hammer spur is a real benefit.

Build quality and reliability get strong marks. Users report consistent function across .357 Magnum and .38 Special loads, and the stainless finish holds up well to daily carry conditions.

The DAO trigger generates the most varied feedback. Many users appreciate the smooth, consistent pull; others find it heavier than preferred, especially for accurate shooting under stress. This is inherent to the DAO design rather than a defect.

.357 Magnum recoil from a 22.1 oz compact revolver is substantial, and this comes up frequently. Most owners manage it with practice; a number use .38 Special +P as their carry load for reduced felt recoil.

The fixed sights are generally accepted for a defensive carry revolver, though users who want adjustable options for longer-range work note the limitation. The 5-round capacity is a standard trade-off discussion point compared to semi-auto alternatives.