The Ruger Mark IV 22/45 Collector's Series is a semi-automatic pistol chambered in .22 LR with a 5.5-inch threaded bull barrel and a blued finish. The receiver is blued alloy steel paired with a blued polymer frame, and the grip is engraved American walnut. It has a 10-round capacity. 
 

Key Specifications 

• Brand: Ruger 
• Model: Mark IV 22/45 
• Caliber: .22 LR 
• Action: Semi Auto 
• Barrel Length: 5.5 in 
• Capacity: 10+1 
• Color: Blued 
   

Detailed Features 

• 5.5-inch threaded bull barrel with blued finish 
• Blued alloy steel receiver 
• Blued polymer frame 
• Engraved American walnut grip 
• 10-round capacity

Owners of the Mark IV 22/45 Collector's Series tend to appreciate the combination of the engraved walnut grip and the all-blued finish; most describe it as a clean, classic look that stands apart from standard polymer-grip versions. The 22/45 grip angle draws the comparison to a 1911-style hold, which is either a plus or a neutral depending on what the owner already shoots.

The 5.5-inch threaded bull barrel is a practical touch that gets used: many owners mount a suppressor and report the Mark IV cycles .22 LR reliably in that configuration. The trigger on the Mark IV platform generally gets positive marks, though a small number of owners note it feels slightly heavy out of the box and improves with break-in.

The Collector's Series label means limited availability and a price premium over standard Mark IV models. Buyers focused purely on function sometimes feel the engraving and walnut add cost without adding utility; those who value the aesthetics see the premium as reasonable for a pistol they also plan to shoot regularly.