The Pietta King Trio is a single-action revolver that ships with three interchangeable cylinders chambered in .38 Super, 9mm, and .357 Mag/.38 Special respectively. The barrel is 4.75 inches. This configuration allows the shooter to use four common handgun calibers from one frame by swapping cylinders. 
 

Key Specifications 

• Brand: Pietta 
• Model: King Trio 
• Caliber: .38 Super / 9mm / .357 Mag / .38 Special (3 cylinders) 
• Action: Single Action 
• Barrel Length: 4.75" 
   

Detailed Features 

• Three interchangeable cylinders included 
• Cylinders cover .38 Super, 9mm, and .357 Mag/.38 Special 
• 4.75-inch barrel 
• Single-action revolver mechanism 
• Allows use of multiple rimless and rimmed calibers from one platform

Owners of the King Trio find the multi-cylinder concept to be its main draw. The ability to run 9mm moon-clipped loads or .38 Super out of the same frame as .357 Mag appeals to shooters who want versatility without buying multiple revolvers. Cylinder changes are straightforward once you learn the sequence.

Single-action trigger pull on Pietta revolvers generally gets positive marks for being crisp and consistent. Some users note that fit and finish on Pietta products can vary from unit to unit, and a light action tune is common practice among owners who shoot them regularly.

The King Trio attracts both range shooters and collectors who like the novelty of the setup. The common complaint centers on sourcing moon clips for the 9mm cylinder. Those who primarily run .357 Mag or .38 Special tend to report the most straightforward experience.