On the subject of answering questions; this one is still outstanding.

Quote:
That works for your bullet and gun, but don't you run into problems if the propagant is a photon?


The point of asking this was to look at the breakdown of SR when the speed of light is involved.
Eg. in the case of the bullet and gun, either can be considered as stationary (depending on the RF), but, as I understand it, there is no RF in which the photon could be considered stationary, whatever motion one attributed to the emitter.

There never was nothing.