This is part of the problem when discussing firearms. A lot of people simply do not understand them, so throw around all sorts of random garbage, simply because that is the way they believe they should be. I see things like this all the time.
For example, the mention earlier in this threat about a "double action" revolver being considered "semi-automatic". No, it is not, it is a revolver. A semi-automatic weapon stops when it reaches the Firing phase, and the next trigger pull is what starts the rest of the cycle. In a semi-automatic weapon, the cycle stops at locking. In a machine gun, it stops after cocking.
And what I am talking about is the "8 cycles of operation". Starting from the beginning, they are:
Firing (gun goes BANG)
Unlocking (in non-revolvers, this is unlocking the bolt from the barrel)
Extracting (pulling the cartridge from the barrel)
Ejecting (kicking the spent round from the weapon)
Cocking (moving the hammer so it is prepared to fire again)
Feeding (pulling a new round out of the magazine)
Chambering (inserting the round into the barrel)
Locking (locking the bolt to the barrel, so weapon is ready to fire)
revolvers ignore/combine several of these, since they have no "chamber", rounds are pre-loaded into the cylinder. So all are seated, there is no ejection, and no bolt is involved to lock. Pulling the hammer back (manually in single action or by trigger squeeze in double action) rotates the cylinder and pulls the hammer back 9cocks the weapon).
Machine guns are only different in that they fire from the "open bolt", as opposed to rifles, which fire from the closed bolt.