Glock has become one of the most popular and widely used pistols in the world. Due to their rugged reliability , ease of use, availability of aftermarket accessories and interchangeable parts. They have become a favorite with law enforcement and competition shooters.
Because parts are so interchangeable between most models it is easy to convert your gun back and forth between different calibers. Full size models in 9mm 40, 357 share the same frames and will accept generations 1,2, and 3 slide assemblies in the before listed calibers . The same is true for the compacts, and subcompact models. ( note that because of the use of a double captured recoil spring the subcompact models will also interchange with the Gen 4 models. )
For example if you currently have a model 22 gen 1, 2 or 3 chambered in 40 s&w and you want to shoot more affordable less recoiling 9mm. Simply add a g17 slide assembly and magazine.
The 45acp and 10mm models share the same frames so slides, frames and magazines are interchangeable between those models.
Gen 4 series only work with gen 4 components. An exception to this is the sub compact models, which can be interchangeable with gen 4 slides, and receivers.