The Smith & Wesson 638 Airweight is a double/single action J-frame revolver chambered in .38 Special +P with a 1.875-inch barrel and 5-round capacity. The frame is aluminum alloy at 15.1 oz; the barrel and cylinder are stainless steel. Overall length is 6.31 inches. The enclosed hammer (shrouded, with the spur tip exposed) allows both double-action firing and single-action cocking for precision shots, while eliminating most of the snag risk during a concealed draw. The matte silver finish combines the aluminum frame with stainless components. Rated for continuous +P use. 
 

Key Specifications 

• Model Name: 638 Airweight 
• Brand: Smith & Wesson 
• Caliber: .38 Special +P 
• Action Type: Double / Single Action 
• Capacity: 5 rounds 
• Barrel Length: 1.875 inches 
• Overall Length: 6.31 inches 
• Weight: 15.1 oz 
• Frame Material: Aluminum Alloy 
• Finish: Matte Silver with Stainless Steel components 
   

Detailed Features 

The shrouded hammer is the key differentiating feature versus the 642 (fully internal hammer). The 638 exposes just the top of the hammer spur, allowing single-action fire for deliberate shots at longer range, while still reducing snag potential compared to a conventional exposed hammer. The stainless steel barrel and cylinder provide corrosion resistance. The aluminum frame keeps weight to 15.1 oz. +P rating means it handles higher-pressure defensive loads without concern. 
 

Target Audience 

Carry users who want the option to cock the hammer for single-action shooting, unlike the fully DAO 642. Suitable for both concealed carry and as a range training revolver where single-action capability is useful for marksmanship work. 
 

Usage Scenarios 

• Concealed Carry: The low weight and snag-reduced profile work well for pocket and IWB carry. 
• Everyday Carry: The DA/SA action offers more flexibility than a DAO revolver for shooters who practice precision shots. 
• Range Training: Single-action capability allows slower, deliberate practice for marksmanship development.

The S&W 638 Airweight draws largely positive feedback as a carry revolver, with discussions typically centered on the DA/SA action and its practical implications.

The weight, 15.1 oz, earns consistent praise for all-day carry comfort. The shrouded hammer design is popular among users who want the option to shoot single-action without the full snag risk of a conventional exposed hammer; this is the 638's primary advantage over the all-internal-hammer 642. Reliability is a recurring positive, as J-frame revolvers in general have a track record for consistent function. The .38 Special +P rating and stainless components are appreciated for defensive use in varied conditions.

The predictable criticisms: the lightweight frame amplifies felt recoil from +P loads, particularly during extended range work. Shooters who train primarily with hot defensive ammunition find that a heavier revolver or semi-auto is more comfortable for volume practice. The 5-round capacity invites comparison to higher-capacity semi-autos. The DA trigger, while usable, requires meaningful practice to shoot quickly and accurately, an honest limitation for buyers who won't invest range time. Factory sights are minimal and have drawn requests for aftermarket improvement from precision-minded users.