Glock 18 vs Glock 17/19?????????? Beretta 92fs vs full auto?
The G18 was supposedly designed specifically to have different internal parts and a frame and slide that are not interchangeable with the G17.
The Beretta 93R was a variant of the older Beretta 92 with frame-mounted controls. I don't know how different it is internally from the Beretta 92FS with slide-mounted controls.