Originally Posted by
zaitcev
About the "M4 cuts" in the feedramp, I tried to public-source serial numbers on GlockTalk. The picture is rather murky, the barrels with the cut and without the cut seem to be mixed in middle of the range. I have both and never noticed any difference in reliablliity, although of course it depends on the tolerance stacking. I feel like it might have been an experiment to fix some issue, which might have been abandoned.
Remember how Glock struggled with the premature slide lock-back on G42. At first they thought it was just QC. They swapped parts by warranty and hoped it would go away. Then, they decided that it must be the slide stop lever and revised it. That did exactly nothing. Only then they gave up and re-designed the magazines with the ridge that pushes bullets to the right (the "03" magazine). So in the end, the original slide stops were fine and they could return to the original spec if they wanted. Perhaps with barrels they did return, if old barrels were cheaper to make.