Read Lucien Haag's study that I posted above. I admit, his analysis wasn't on the internet, but was peer reviewed and published in a major medical journal.
What about the Warren Commission's testing of the recovered Carcano rifle? I believe their finding could be summarized as "couldn't hit the broadside of a barn"? Specifically, if memory serves that the optic and mounts were not correct?
That leaves us with three potential scenarios: 1.) The report in the Warren Commission about a 7.92 Argentine Mauser at the Book depository may hold some weight, 2.) Oswald was a terrible shot and got really lucky, 3.) Additional Shooter/s?