It's all a sideshow Steve to the main event ie new forensic tests/CoA.
That will mean absolutely b....r all. Here is a quote from a study you might want to read you'll need to buy it though - however, it completes the challenge you set me. Still waiting for you to complete yours
Shots Fired with Silencers A Report on Four Cases and Experimental Testing
Johann Missliwetz, 1 M. D.; Wolfgang Denk, 2 M.D.," and Ingo Wieser 3
"Any assessment beyond doubt would only be possible if
the used silencer were recovered for examination"
"The presented case also shows how easily a shot fired with a silencer can be mistaken for a shot fired without silencer when neither weapon nor the silencer are available for examination"
Like I have been telling you, any test would need to be undertaken with the actual murder weapon and silencer and even then you would have to prove that your findings (if they were different) - weren't down to chance and even then it wouldn't prove that on that day in 1985 that the conditions were suitable to allow blood to enter the silencer via drawback. I should also add, that in this study drawback did occur and was evident inside the silencers - which you said was impossible!