Interesting from everything I was seeing was no gunsmithing needed you just need to be able to install the different part kits. That was why I started the thread to find this sort of thing out, so thank you. If I ever do try to build one myself from the ground up I will have to ask the slide manufacture if that is still the case.Many years ago I was at the SHOT show and Caspian had a stainless steel slide for the Glock 19 - Had to have it!! Wasn't cheap either. When I finally got around to getting all the internals for it I was told that it needed to be gunsmithed a bit to get the parts to fit It's in the bottom of my spare parts/holster/stuff tote. So much for my custom Glock.