The Ruger Mark IV 22/45 Lite is a semi-automatic .22 LR pistol with a 4.4-inch barrel, 10-round capacity, and a black frame with red anodized receiver. It weighs 25 oz. 
 

Key Specifications 

• Brand: Ruger 
• Model: Mark IV 22/45 Lite 
• Caliber: .22 LR 
• Action Type: Semi-Automatic 
• Capacity: 10 rounds 
• Barrel Length: 4.4 inches 
• Overall Length: 8.4 inches 
• Weight: 25 oz 
• Frame Finish: Black with Red Anodized Receiver 
• Safety Feature: Manual Thumb Safety 
   

Features 

 
The polymer grip has a black diamond checkered texture with a grip angle designed to mimic a 1911, which is where the "22/45" name comes from. Adjustable rear sights pair with a fixed front. The barrel is threaded 1/2x28 for suppressor use. 
 
One-button takedown is a genuine improvement over earlier Mark designs. Field-stripping no longer requires tools or memorizing a disassembly sequence. The bolt stop is ergonomic and easy to operate single-handed. 
 
At 25 oz the gun is light enough to carry comfortably and the .22 LR cartridge keeps training costs reasonable for extended range sessions.

The Mark IV 22/45 Lite gets a consistent thumbs-up from the .22 LR community.

Ergonomics and the 1911-style grip angle are frequently praised, particularly by shooters who use it as a training complement to a larger-caliber carry gun. Accuracy at range is a common highlight. Most owners report tight groups. The lightweight aluminum frame is appreciated for all-day carry and range use. Reliability is solid with quality ammunition, though some users note occasional jams with lower-grade bulk ammo.

Disassembly, while improved from the Mark III, still generates some complaints from those who find the process less intuitive than other modern pistols. The black/red finish is polarizing. Some like the look, others would prefer more subdued options. The suppressor-ready threaded barrel draws positive attention from owners interested in that use case. Overall the gun is viewed as a strong value in the .22 LR segment.