In "Ayoob: Compact Springfield Echelon 4.0C Review" by Massad Ayoob, the article reviews the new Springfield Armory Compact Echelon 4.0C pistol, a smaller version of the 4.5F model chambered for the 9x19mm Parabellum cartridge. A key feature of this handgun is its modular Central Operating Group and Variable Interface System, which support various red dot sights without adapter plates. The Echelon 4.0C is designed as a compact, user-friendly version with a 4-inch barrel and a 15-round magazine capacity, expanding versatility for concealed carry. During testing, the gun shows reliable performance with no malfunctions across different users and conditions. The pistol's well-designed trigger, ergonomic grip with adaptive texture, and compatibility with everyday carry gear make it an appealing option for personal defense, with suggestions of its potential popularity among gun enthusiasts.