ok, So i just got done reading Jerry Kuhnausen principles of the 1911. Big question ? Without assuming what moves the slide after the bullet leaves the barrel and after reading Jerry Kuhnausen principles of the 1911. Don`t you think That the Head of the casing starts to push the slide rearward AFTER the casing Relaxes from being expanded for that millisecond. The casing Expands creates friction in the chamber wall then decides to move backward. I wonder if the extractor is even needed. There is no other force applying pressure to the slide other than the casing itself. So my question is if none of this is true what is creating the movement. ( AK47, gas block + expanded gas + piston = bolt carrier movement )