The fact is the bullet was taken out of chain of custody and is not reliable proof of much of anything. We don't know that this bullet came from either Ramos or Campeon, this guy could have been shot by a buddy down in Mexico for all we know. This is why they have chain of custody and Sanchez had to know this when he took the fragment with him to his home with Davila for the night.
Until we see the court transcript, we won't know if there was any evidence presented that the bullet was from Ramos' gun.
I suspect there was not, since the story is Ramos STIPULATED that the bullet was from his weapon. When the prosecution and defense stipulate to a fact, it is rare to present any evidence regarding that fact.
Using stipulation so that you can later claim there was no "evidence presented" is a good rhetorical trick, and might work with politicians and a gullible public, but I doubt the appeals court will look kindly on that sort of argument.
But still, my point wasn't to argue if the bullet was Ramos' or not. As I pointed out elsewhere, we KNOW Compean wasn't claimed to have hit him, but Compean got more total time than Ramos -- and Ramos admits he shot at the guy. "attempted" applies whether you are a good shot or not.
My point was that, if we accept the claim that the bullet was NOT Ramos' bullet, then the medical report gives NO backing to the claim that Ramos was threatened, since the bullet wound does NOT indicate that the smuggler turned toward Ramos, because the wound was not inflicted by Ramos.
This is what I mean by being consistant and addressing the facts. It is actually pretty easy to take things in tiny pieces and make up stories that sound like they back your position, but if those stories are inconsistant with each other, and inconsistant with the known facts, all you've really done is told a poorly constructed fairy tale.