Smith & Wesson Model 637 Airweight
Smith & Wesson · Pistol · In Production · 1996
Also known as: 637 Airweight, Chiefs Special Airweight, 637-1, 637-2
Overview
The Smith & Wesson Model 637 Airweight is a five-shot, double-action/single-action J-frame revolver chambered in .38 Special and rated for continuous +P use. It is the stainless steel and aluminum alloy evolution of the classic Model 37 Chiefs Special Airweight, combining a lightweight aluminum alloy frame with a stainless steel barrel and cylinder for corrosion resistance. The Model 637 features an exposed hammer that permits both double-action and single-action fire, distinguishing it from the enclosed-hammer Model 642 Centennial series. At just 14.5 ounces (411g) unloaded, the 637 is one of the lightest practical defensive revolvers available. The 1.875-inch (48mm) snub-nose barrel delivers typical .38 Special +P velocities of approximately 790 fps (240 m/s) with 130-grain loads. The double-action trigger pull is approximately 12 pounds (53 N), with a crisp single-action pull of approximately 4-5 pounds (18-22 N) when the hammer is manually cocked. Fixed sights consist of an integral front ramp and a fixed rear notch milled into the top strap. The matte silver finish provides a professional appearance and resists corrosion in humid environments or when carried against the body.
Specifications
| Weight (empty) | 411 g (14.5 oz) |
| Weight (loaded) | 476 g (16.8 oz) |
| Overall Length | 160 mm (6.30") |
| Barrel Length | 48 mm (1.89") |
| Height | 109 mm (4.29") |
| Width | 33 mm (1.30") |
| Sight Radius | 90 mm (3.54") |
| Action Type | Double Action |
| Firing Mechanism | Double Action Single Action |
| Trigger Type | Double Action |
| Trigger Pull | 53 N (11.9 lbf) |
| Magazine Capacity | 5 rounds |
| Muzzle Velocity | 240 m/s (787 fps) |
| Muzzle Energy | 233 J (172 ft·lbf) |
| Effective Range | 15 m (16 yd) |
| Barrel Rifling | Right Hand |
| Rifling Twist | 476 mm (18.74") |
| Number of Grooves | 5 |
| Frame Material | Aluminum Alloy |
| Barrel Material | Stainless Steel |
| Finish | Matte Silver |
Calibers
- .38 Special · primary — also known as .38 Spl, .38 S&W Special, 9.1x29mmR
- .38 Special +P — also known as .38 +P, .38 Spl +P, .38 Special Plus P
Features
- Firing modes: Semi Automatic
- Feed systems: Revolver Cylinder
- Safety mechanisms: Hammer Block Safety, Internal Lock
- Features: J Frame, Exposed Hammer, Aluminum Alloy Frame, Stainless Steel Cylinder, Stainless Steel Barrel, Integral Front Sight, Fixed Rear Sight, Synthetic Rubber Grip, Rated Continuous Plus P, Five Shot Cylinder, Snub Nose Barrel
Variants
- S&W Performance Center Model 637 — Performance Center
- S&W Model 637 with Crimson Trace Lasergrips — Laser Equipped
- S&W Model 37 Airweight (Blued) — Finish Variant
Base model
Service history
Operators
- U.S. Civilian Concealed Carry Market
- U.S. Law Enforcement (Backup/Off-Duty) · as Authorized Backup Weapon
Production
Production years: 1996-present
Continuous production since 1996; successor to the Model 37 Airweight lineage dating to 1952
Origin
Country of origin: United States
Notes
The Model 637 is the stainless/aluminum counterpart to the original blued Model 37 Chiefs Special Airweight, which was introduced in 1952 as the lightweight version of the Model 36 Chiefs Special. The current 637 designation was adopted in 1996 when Smith & Wesson updated the model with modern materials and the internal lock mechanism. The exposed hammer gives the 637 a tactical advantage over the hammerless Model 642 by allowing single-action fire for more precise shots when time permits, but the protruding hammer spur can snag on clothing during a hasty draw from concealment. Many experienced carriers prefer the 637's versatility, using double-action for close encounters and thumbing the hammer back for deliberate shots at longer distances. The lightweight aluminum frame transmits significant felt recoil with +P loads, and most instructors recommend standard-pressure .38 Special for practice. The Performance Center variant features a tuned action with approximately 9-pound DA and 2.5-pound SA trigger pulls. The loaded weight estimate includes five .38 Special +P cartridges at approximately 13g each. MSRP is approximately $469. The 637's rifling twist rate is 1:18.75 inches (476mm) with 5 grooves, right-hand twist.
Background
The Chiefs Special Airweight lineage began in 1952 when Smith & Wesson created the Model 37 by fitting the Chiefs Special with an aluminum alloy frame, shaving nearly a third of the weight. The concept was revolutionary at the time -- a full-power .38 Special revolver light enough to carry in a jacket pocket all day without discomfort. The Model 637 continues that tradition as one of the lightest exposed-hammer revolvers in production, favored by shooters who want the option of single-action accuracy without sacrificing the concealability of a J-frame snubnose.