The E-Frame served as the basis for forthcoming I-Frame platform used for the Python and the Trooper.

The OP was built on what would become known as Colt’s “E-Frame.” It was smaller than the original “New Service” frame, but bigger than the newer “D-Frame” guns-which include the Police Positive (because what cop doesn’t appreciate positivity?) and later the Detective Special. Army did adopt Colt’s “New Service” model (the successor to the M1889) as the M1909… New Service, Too Lateīy the time Colt perfected the V-Spring platform, the revolver’s days as a military-service sidearm were numbered. This remained a hallmark of Colt’s DA revolvers, becoming known as the “Bank Vault Lockup.” It’s a feature that differentiates Colt revolvers from S&W revolvers to this day.Ĭollectively, these elements constitute Colt’s “V-Spring Action.” And it was the only type of DA action Colt offered until 1969, when the Trooper MKIII (which, again, is unrelated to the I-Frame Trooper. The 1889’s action was designed to lock the cylinder in place when the trigger was pulled. This allowed for faster loading while leaving the top-strap intact/connected-which became critical as Colt evolved their DA platform to handle higher-pressure cartridges that S&W’s “top-break” guns could not.Ī Trigger-Locking Cylinder. The DA lockwork they designed around this “V-spring” proved far superior to Colt’s earlier DA designs-which consisted of fragile, fiddly mechanisms shoehorned into Single-Action Army frames (basically).Ī Swing-Out Cylinder. With the M1889, Colt began using a distinctive flat-wire mainspring folded into the shape of a V. And while the 1889 platform was still fairly crude at that point, it introduced 3 key innovations that remained constants in Colt’s revolvers for the next 80-some years:Ī V-shaped mainspring.

Colt new service revolver frame size