ridgerunner
I'm not sure exactly what you're asking here.
If you buy ANY centerfire rifle, you can fit ANY centerfire NEF barrel on it except for the 10ga shotgun. Note, I said centerfire, since you cannot put a rimfire barrel on the centerfire receivers or vice versa.
All you really need is to buy ONE rifle and get the extra barrels later. It has to go back to NEF for the barrel purchase and initial fitting, after that you swap them yourself.
Is that what you're asking?