Considering he is in a crowd of angry gun obsessed extremists who have been cultivated to reject reality, I think there is a decent chance that this was one of his own. Maybe someone was pissed that he softened his stance on abortion. The so-called "pro-lifers" have murdered before.
We’re never going to know for certain. If they have a dead “gunman” then Trump Inc. gets to write their backstory. Bets that it somehow ends up being a “liberal” with a secret manifesto to be found later.
If only there was a good guy with a gun, they could have prevented this. Where, oh where, in a Pennsylvania right wing convention can be found a good guy with a gun?
I'm not a great shot and I can easily shoot a 2" grouping at 600 ft. I've hit moving deer in the woods at around 500 ft. It's not a hard shot if you know what you're doing.
If he had aimed center mass, like a competent shooter would, Trump would probably be dead.