"Again, a bullet at z272 is after z250."
So is a bullet at Z251 and Z313 and everything in between. This is bar none the most ridiculous explanation that could have been offered. You are just trying to cover all the options because even you realize the implausibility of this theory.
All in all this appears to be the same useless discussion that it always is. Start with a goofy theory about a shot at Z270 and now an added "after" Z250 shot coupled with an inability to support either shot. Then add in the usual tortured witness analysis and use the HSCA report to support the analysis. Ignore the fact that the people who wrote the HSCA report stated it was wrong and why.
It takes two to make a useless discussion. In any event, your theory that the overwhelming evidence of three shots and a 1......2...3 shot pattern being wrong is no less goofy than my "theory" that the evidence is not wrong.
The HSCA did a lot of useful things. But their comment about the supposed general unreliability of witnesses was a poor attempt to justify why none of the witnesses heard a phantom 4th shot that they concluded was fired. In fact, there was no such shot.
You have a long way to go to show that the witnesses, all 132 of them, thought they heard a phantom 3rd shot that did not exist. BTW, what is your explanation as to how the "three shot" witness tampering got started? Why did so many witnesses go along with it?