Sounds like a starter kit. Don't you know that you only really need one, maybe 2 glocks. To start get the Glock 20, a 10mm. Then, using mostly just barrels and mags, sometimes extractors and RSAs, you can end up with: .50 GI, .460 Rowland, .45 Super, .45 ACP, .38 Super, 9mm, .40 S&W and finally...