I think its a bit contradictory, inconsistent, and ambiguous for the ballistic expert, Malcolm Fletcher, to conclude that he can find no association between any of the 25 crime scene bullets and the fact that any of them were or had been fired through a silencer, and then in the next breath produce a theory to explain how Sheila's blood got into the silencer by claiming it was fitted to the guns barrel at the time Sheila was shot under the chin and killed...
This is a prime example of how the evidence can be manipulated/misinterpreted to help convict an innocent man of crimes he did not, and could not have committed...