Smith & Wesson K Frame Model 18 Cylinder Stop & Spring
Part Number: K509
Condition: Used - Good
Frame: K Frame
Model: 18 Combat Masterpiece
Caliber: .22 LR
Finish: Blued Steel
Includes: Cylinder stop (bolt) and cylinder stop spring
Weight: 1 oz
Product Details
Genuine Smith & Wesson factory cylinder stop and spring assembly for the K Frame Model 18 Combat Masterpiece revolver. This critical timing component locks the cylinder in precise alignment with the barrel for each shot. The assembly includes both the cylinder stop (also called the cylinder bolt) and the cylinder stop spring. Essential for maintaining proper cylinder timing and lockup in your classic .22 target revolver.
About the Model 18
The Smith & Wesson Model 18 Combat Masterpiece is a legendary .22 LR target revolver built on the medium K Frame platform. Introduced in 1949 (originally as the K-22 Combat Masterpiece), the Model 18 features adjustable sights, a 6-shot cylinder, and is typically available with a 4-inch barrel. The Model 18 is renowned for exceptional accuracy, smooth trigger action, and reliability. It's extremely popular for target shooting, small game hunting, training, and competitive shooting. The .22 LR chambering makes it economical to shoot while maintaining the feel and handling of centerfire K Frame revolvers.
Cylinder Stop Function
The cylinder stop (also called the cylinder bolt) is a spring-loaded component that rises through the bottom of the frame to engage notches in the cylinder, locking it in precise alignment with the barrel. Proper cylinder stop function is absolutely critical for accuracy, safety, and reliable ignition. The cylinder stop must engage at exactly the right moment during trigger pull and hammer fall to ensure the chamber is perfectly aligned with the barrel and firing pin.
Function & Compatibility
The cylinder stop works in conjunction with the hand to control cylinder rotation and timing. As you pull the trigger in double-action, the hand rotates the cylinder while the cylinder stop drops down to allow rotation. At the precise moment of lockup, the cylinder stop rises to engage the cylinder notch, locking everything in alignment. This timing must be perfect for safe and accurate operation. The cylinder stop spring provides the tension needed for proper engagement.
This cylinder stop and spring assembly is specifically designed for Smith & Wesson K Frame Model 18 revolvers chambered in .22 LR. It may also fit other K Frame .22 models - contact us to verify compatibility for your specific revolver.
K Frame .22 Revolvers
The Model 18 is part of Smith & Wesson's K Frame .22 family, which includes the Model 17 (K-22 Masterpiece with 6-inch barrel) and Model 48 (K-22 Masterpiece MRF in .22 Magnum). These revolvers are highly regarded for training, competition, and recreational shooting. The K Frame size provides excellent handling and pointability while the .22 LR chambering offers low recoil and economical ammunition. Proper timing is critical for the accuracy these revolvers are famous for.
How to Identify Your S&W Model
To determine your Smith & Wesson revolver model number, swing out the cylinder and check behind the yoke on the frame for the model number stamped into the metal. You should see "18" or a dash variant like "18-1", "18-2", etc. Model numbers began in 1957-58. If no model number is present, your revolver may be a pre-model K-22. Contact us with your serial number for assistance in identifying the correct parts.
Installation & Specifications
- Professional gunsmith installation strongly recommended
- Requires disassembly of internal action components
- Critical timing component - must be properly fitted
- Improper installation can cause timing issues and safety hazards
- Cylinder stop must engage cylinder notches at precisely the right moment
- Factory OEM parts manufactured to exact S&W specifications
- Used parts inspected for wear and functionality
- Compatible with K Frame Model 18 .22 LR revolvers
- May fit other K Frame .22 models - verify compatibility
- Includes both cylinder stop and spring
- Spring tension must be correct for proper function
Timing & Performance Notes
The cylinder stop is one of the most critical components affecting revolver timing and accuracy. It must engage the cylinder notches at precisely the right moment to ensure proper barrel-cylinder alignment. Worn or improperly fitted cylinder stops can cause accuracy problems, cylinder binding, light primer strikes, or dangerous timing issues. Proper timing ensures the chamber is perfectly aligned with the barrel and firing pin for reliable ignition and maximum accuracy - essential for the precision shooting the Model 18 is designed for.
Condition Notes
This is a used OEM cylinder stop and spring assembly removed from a functioning Smith & Wesson Model 18 Combat Masterpiece revolver. Shows normal wear consistent with use. All engagement surfaces have been inspected for excessive wear or damage. Spring tension is good. Used parts may show finish wear or handling marks typical of fired revolvers. Both cylinder stop and spring included. Guaranteed to function properly when correctly installed.
Contact Us
We specialize in Smith & Wesson pistol and revolver parts - used, new old stock, refurbished, and new. Our team has extensive knowledge of S&W firearms and can help you find the exact parts you need for your K Frame revolver.
Questions? Email sales@usagunsandgear.com or call 770-544-8075