I was present at Birdwell Armoury when tests were done to try to recreate mark impressions on the skin of a living person - the weapon used was a model 525 anshuzt semi-automatic rifle, fitted with a 17 baffled Parker hale silencer. The model / victims name was Amy Holland. The weapon handler was Glen Smith / Keith Mallinson...
These experiments and the results which were produced on this occasion were captured on film and video footage, and provided physical proof that the end of silencer had been pressed against the victims skin and left a visible impression there, comparable to the mark which is present around the lower wound in Sheila Caffell's neck! The chief differences were, however, that in the experiments conducted no shot was fired in that contact position!
This gave cause to consider the implication of a duplication of such a mark around the lower wound site in Sheila Caffell's neck, albeit accompanying a shot?
Smith and Mallinson were mindful of Malcolm Fletcher's range tests, and his findings in relation to the distance of the muzzle of the weapon from the surface of the skin at the time that lower shot was taken (if my recollection serves me correctly, Fletcher stated that the shot had been a near contact one, within 3" or so). Smith and Mallinson did there own range tests at Birdwell Armoury, using a model 525 anshuzt rifle, a 17 baffled Parker hale silencer, and Ely .22 LR subsonic hollow point ammunition. These tests ranged from contact with the target paper, 1", 3", 6", and 9" or so. These tests were done on two separate pieces of target paper, one piece of paper for all the shots minus a silencer, and another piece of target paper for the series of range shots where a silencer was used!
After the tests were completed they examined the results against the lower bullet entry wound in Sheila's neck!
They concluded that in fact the lower neck wound in this instance had been a contact shot!
These conclusions were reported to Ewen Smith at his Birmingham offices!