I doubt this matters most of the time but I have a feeling that some semi's are near ''brutal'' with the loads imposed on rounds. They collide with feedramp and then have to change direction to ''find'' the chamber - pretty abruptly!
This why the top round of a mag should maybe not be always the one to be rechambered after an empty and recharge sequence.
I wonder too tho - and this is a manufacturer thing - which brand of ammo is most resistant to any set back thru frequent chambering.
I am for most part a GD fan and have to say - I cannot notice too much ''distress' with rounds that have already been slammed into battery a time or two. That said - I rotate rounds when reloading so top one is ''fresh". I think this varies too - gun by gun.
Eventually of course the carry inventory gets shot up and fresh used.