The pressures experienced in a real firearm breach and barrel are immense, so the components of a real steel firearm are built to over compensate, the construction of a blank firing pistol even if steel would not be sufficient to handle the pressures and kinetic forces exerted during firing a live round, even the slide would probably become a lethal rearward projectile, I remember seeing footage of the original Beretta 92 range tests where a topslide failed during firing injuring the shooter.