Hey all Called Glock yesterday to ask about the new Gen. 4's coming out. I was mainly interested in the changes being made internally. I want to know if I will be able to keep getting parts for my older guns. Here's what I was told I know a lot of people have been wondering. All the internals are the same as gen after gen the main change is the recoil system is not interchangeable with the other gen. So I quote (You won't need to worry about parts for you older Generation Glocks.) And as to when the other Cal glocks will be coming in Gen 4, could not get a time frame on that.