Assuming the recoil spring is in right, stick an empty magazine in the gun and rack the slide with a 4-finger overhand grip at the BACK of the slide. You may be tempted to grip the front of the slide so you can see the slide stop lever and notch: DON"T or you can end up with bloody, lacerated fingers. Compared to other pistols, the Shield slide locks much further aft than you'd expect.