The FN 502 MRD FDE is a .22 LR SAO pistol with a 4-inch barrel, 10+1 capacity, and 22.50 oz weight. The frame is FDE textured polymer; the slide is optics-ready and accepts a wide range of red dot sights. Manual safety is ambidextrous. Overall length is 7 inches with optic-height sights standard. 
 
Key Specifications 

• Model: FN 502 MRD 
• Caliber: .22 LR 
• Action Type: Single Action Only (SAO) 
• Capacity: 10+1 rounds 
• Barrel Length: 4 inches 
• Overall Length: 7 inches 
• Weight: 1.41 lbs (approximately 22.50 oz) 
• Grip Material: FDE Textured Polymer 
• Safety: Ambidextrous manual thumb safety 
• Sights: Optic Height Sights 
• Finish Color: Flat Dark Earth 
   
  Detailed Features 
  The single-action trigger gives a consistent, relatively light pull that helps shooters build good habits without fighting a heavy DA stroke. The optics-ready slide is the standout feature in this category. Pairing a red dot with a .22 trainer cuts practice costs while keeping the aiming system familiar. The polymer construction keeps weight low and the FDE finish distinguishes it from standard black variants.

The FN 502 MRD FDE gets strong marks for build quality. Owners report it feels solid and the fit and finish are noticeably above budget .22 trainers. The optics-ready design is frequently cited as the reason buyers chose it over alternatives; mounting a red dot for practice without running expensive centerfire rounds is a practical benefit.

Accuracy feedback is positive across different ranges. The trigger draws the predictable split: adequate for most, not quite crisp enough for a subset who want more from a SAO design. Price relative to other .22 pistols is debated, though most buyers who prioritize optics compatibility find it justified. Holster options and aftermarket accessories are still thinner than for established platforms. Some owners note the gun needs a break-in period before running smoothly with certain ammunition.