The “Baby Glocks” first came out in 1996. And with this release came a new pattern in Glock developement; new models would bring new features that would become part of the next generation development–sometimes years ahead of their time. The baby Glocks were the first to incorporate finger grooves in the front strap, ostensibly to try to help us hold on to these new tiny frames.
It can be hard to distinguish the true “Gen 2.5s” unless you’re in to the small details. There are two different classifications that earned this distinction.
- Models 26 and 27 have smooth finger grooves–the only thing that distinguishes them from Gen 3s.
- Models 20 and 21 were the first large frames to get finger grooves–these ones with checkers–but did not come with the new Glock rail that was part of the Gen 3 design.
The models 20C and 21C are especially difficult to track down being that Cs were new, the transitional frames were only made for a few months, and also that these calibers weren’t nearly as popular as the 9mm or .40 S&W.
A Brief History of Glock Firearms Aimed at Collectors 