Thanks for the support.
On re-read, I think the OP just didn't express what he meant clearly until his second post. By "definitive proof" I believe he meant he had proved that in his gun with his ammo component combination he'd shot enough test rounds at different COL's to demonstrate the described effect wasn't shooter error and wasn't a figment of his imagination. He just didn't understand why others weren't reporting the same issue. Hopefully, we're on the way to an answer.
The single shot test will make the magazine follower pressure the same on each round, so the clip stripping forces are the same each time, so the slide closing momentum is the same each time. That and the manual push on the slide should get him into battery the same way each time. Watching the back of the slide to see how close it comes to flush with the back end of the frame after each shot is another good indicator of feed consistency. The exact amount of overlap there isn't critical as long as the gun functions, but that overlap does need to be the same each time for accuracy.
All sides of the discussion should keep in mind that few of us on the forum are professional writers and few of us have the literary skill to accurately convey the subtleties of a grin, a sneer, or a shrug, or to control innuendo precisely. There's no body language to read for backup, so it's easy to read some unintended offense into a post. Unless it's spam, the default mode should be to give the apparent offender the benefit of the doubt. I got the wrong idea here initially, too.
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