Smith & Wesson M&P .40 S&W Locking Block Used – Part# MP4015E

Smith & Wesson M&P .40 S&W Locking Block – Used

Part Number: MP4015E  |  Condition: Used (Factory Original)  |  Caliber: .40 S&W

Restore your M&P .40 to factory-correct function with this genuine Smith & Wesson replacement locking block. The locking block is a critical fire control component that locks the barrel into battery during firing — proper fit and function are essential for safe and reliable operation.

• Part Number: MP4015E
• Fits: Smith & Wesson M&P .40 S&W (full-size)
• Caliber: .40 S&W
• Condition: Used – factory original S&W part
• Installation: Gunsmith fitting recommended

Compatibility Note

This locking block is specific to the full-size M&P .40 S&W. It is not interchangeable with the M&P Shield or 9mm M&P locking blocks. If you are unsure of compatibility, contact us with your model and serial number.

Factory Replacement Quality

Genuine Smith & Wesson factory parts are manufactured to the exact specifications and tolerances of the originals — same materials, same dimensions, same reliable function.

Professional gunsmith installation recommended. Some parts may require fitting.