Gator you just contradicted yourself.
First you said the ME doesn’t list a specific caliber.
Then you say Medium is an official term and refers to the caliber.
Which is it? If the ME says Medium and Medium means .38 then the ME is listing the caliber.
Its hard to believe no bullets have been recovered. The specific caliber should be pretty easy to determine from the large sample they have.
I think the “medium” term is being used to give the illusion of providing an answer, when none is actually given. As TG said, so as not to give the prosecution any trouble. (Sometimes a little bit of truth slips out with all the other words.)