The Colt Firearms M4 Carbine MPS is a semi-automatic rifle chambered in 5.56 NATO. The 16.1-inch barrel is Chrome Moly Vanadium. Receivers are 7075-T6 aluminum. Overall length adjusts between 32" and 35.5". Weight is approximately 6.9 lbs. 
 

Key Specifications 

• Model: M4 Carbine MPS 
• Caliber: 5.56 NATO 
• Action Type: Semi-Auto 
• Barrel Length: 16.1 inches 
• Capacity: 30+1 rounds 
• Trigger Type: Single-Stage 
• Safety Mechanism: Manual Thumb Safety 
• Overall Length (OAL): Adjustable between 32" - 35.5" 
• Weight: Approximately 6.9 lbs 
• Stock Description: Adjustable Magpul SL Carbine Stock 
• Receiver Material: 7075-T6 Aluminum 
• Sights Included: A2 Front Sight, Magpul MBUS Rear Sight 
• Twist Rate: 1:7" 
   

Detailed Features 

 
The Magpul SL Carbine stock adjusts for length of pull across multiple positions. Sights are an A2 front with a folding Magpul MBUS rear -- the rear folds flat when running an optic and deploys quickly when needed. The Chrome Moly Vanadium barrel has good heat resistance for extended range sessions. Single-stage trigger and manual thumb safety are standard Colt spec.

Users discussing the Colt M4 Carbine MPS in 5.56 NATO generally focus on reliability and build quality as strengths. The semi-auto action cycles smoothly and the 16.1-inch barrel is credited for solid accuracy. The compact size and manageable weight are mentioned as positives for handling in tight spaces.

The recurring criticism is price -- Colt rifles tend to cost more than competing AR-platform options with similar feature sets, and some buyers feel the premium isn't fully justified. A few users also note they'd prefer more accessories included from the factory rather than having to source them separately.

Overall, owners who prioritize the Colt name and track record in semi-auto rifles are satisfied, while budget-focused shoppers tend to look elsewhere.