Ruger GP100 4.2"
Sturm, Ruger & Co. · Pistol · In Production · 1985
Also known as: GP-100, GP100
Overview
The Ruger GP100 is a medium-frame, double-action/single-action revolver chambered primarily in .357 Magnum, introduced by Sturm, Ruger & Co. in 1985 as a successor to the Ruger Security-Six line. Built on a solid stainless steel frame, the GP100 is engineered for sustained use with full-power .357 Magnum ammunition, a capability that sets it apart from many competing revolvers. The 4.2-inch barrel model (Model 1705) weighs 40 ounces (1134g), providing a substantial platform that mitigates recoil while remaining practical for holster carry. The GP100's defining feature is its triple-locking cylinder, which engages at the front, rear, and bottom of the crane to ensure precise alignment with the barrel on every shot. The investment-cast stainless steel construction extends throughout the frame, barrel, and cylinder, providing exceptional resistance to corrosion and wear. The action incorporates Ruger's patented transfer bar safety mechanism, which prevents the firing pin from contacting the primer unless the trigger is fully pulled, allowing the revolver to be safely carried with all six chambers loaded. The sights consist of a ramp front sight and a fully adjustable white outline rear sight. Standard grips are Hogue Monogrip rubber grips with finger grooves that cushion recoil effectively. The cylinder accepts both .357 Magnum and .38 Special cartridges interchangeably. The barrel features right-hand rifling with a 1:18.75-inch twist rate and 5 grooves.
Specifications
| Weight (empty) | 1134 g (40.0 oz) |
| Weight (loaded) | 1195 g (42.2 oz) |
| Overall Length | 241 mm (9.49") |
| Barrel Length | 107 mm (4.21") |
| Height | 145 mm (5.71") |
| Width | 40 mm (1.57") |
| Sight Radius | 152 mm (5.98") |
| Action Type | Double Action |
| Firing Mechanism | Double Action Single Action |
| Trigger Type | Double Action |
| Trigger Pull | 53 N (11.9 lbf) |
| Magazine Capacity | 6 rounds |
| Muzzle Velocity | 378 m/s (1240 fps) |
| Muzzle Energy | 732 J (540 ft·lbf) |
| Effective Range | 50 m (55 yd) |
| Barrel Rifling | Right Hand |
| Rifling Twist | 476 mm (18.74") |
| Number of Grooves | 5 |
| Frame Material | Stainless Steel |
| Barrel Material | Stainless Steel |
| Finish | Satin Stainless |
Calibers
- .357 Magnum · primary — also known as .357 Mag, .357 S&W Magnum, 9x33mmR
- .38 Special — also known as .38 Spl, .38 S&W Special, 9x29.5mmR
Features
- Firing modes: Semi Automatic
- Feed systems: Revolver Cylinder
- Safety mechanisms: Transfer Bar
- Features: Triple Locking Cylinder, Adjustable Rear Sight, Ramp Front Sight, Hogue Monogrip, Six Shot Cylinder, Dual Caliber Capability, Full Length Ejector Shroud, Cushioned Rubber Grips
Variants
- Ruger GP100 6" — Barrel Length
- Ruger GP100 3" — Barrel Length
- Ruger GP100 Match Champion — Competition
- Ruger GP100 7-Shot — Capacity Variant
- Ruger GP100 10mm Auto — Caliber Variant
- Ruger GP100 .44 Special — Caliber Variant
- Ruger GP100 .22 LR — Caliber Variant
- Ruger GP100 .327 Federal Magnum — Caliber Variant
Service history
Operators
- U.S. Law Enforcement (Various Departments) · as Authorized Duty/Backup Revolver
- Civilian Sport Shooters & Hunters
- Security Guards · as Authorized Duty Weapon
Production
Production years: 1985-present
Continuous production since 1985 with multiple caliber and configuration variants added over the decades; one of Ruger's best-selling revolver lines
Origin
Country of origin: United States
Notes
The GP100 was designed from the ground up as a working revolver, and Ruger's engineering team focused on making it virtually indestructible. The frame is built as a single investment casting without sideplates, and the internal mechanism is assembled as modular sub-assemblies that drop into the frame, simplifying maintenance and cleaning. The triple-locking cylinder lockup provides one of the strongest cylinder-to-frame interfaces in any production revolver, which contributes to the GP100's legendary reputation for withstanding tens of thousands of rounds of full-power .357 Magnum ammunition without loosening. The GP100 has expanded significantly from its original .357 Magnum chambering to include .327 Federal Magnum (7-shot), .44 Special (5-shot), 10mm Auto (6-shot), and .22 LR (10-shot) variants. The Match Champion variant, introduced in 2014, features a polished trigger, fiber optic front sight, and Hogue hardwood stippled grips, aimed at IDPA and ICORE revolver competition. With a 158-grain .357 Magnum load, the 4.2-inch barrel typically achieves approximately 1240 fps (378 m/s) with 732 joules of muzzle energy. The double-action trigger pull measures approximately 12 pounds (53 N), while the single-action pull is approximately 5 pounds (22 N). The loaded weight estimate includes six .357 Magnum cartridges at approximately 10.2g each.
Background
The GP100 has earned a reputation as the 'tank' of medium-frame revolvers. Competitive shooters, particularly Jerry Miculek, have used GP100 variants in revolver competitions, and the gun has become a favorite recommendation for first-time revolver buyers due to its combination of durability, accuracy, and manageable recoil. Its robust construction has made it the go-to .357 Magnum for shooters who want a revolver they can fire tens of thousands of rounds through without concern.