The Glock lockup isn't like a 1911. The slide to frame fit doesn't have much of anything to do with accuracy. In a Glock, the barrel locks up into the slide and the sights are on the slide. Try moving the muzzle around, on the Glock and mine don't move. The chamber hood locks up into the ejection port and the locking block forces the rear, of the barrel, up. The muzzle is being cammed downward against the slide muzzle port. You can get a small bit of downward movement, of the chamber hood when you push down, but there's nothing to make it move, when firing.