The current trend for providing Forensic Science expertise to the prosecution has swung away from a single all encompassing provider (The Forensic Science Service) to multiple small providers. This we have been told will provide a competitive market. What it also does is disrupts the consistency of methodology, opinion, legal interpretation and technical training which had been provided by the single entity provider.
In my own field of expertise, forensic ballistics, firearms and ammunition examination/classification and microscopy, the changes have been noticeable in the classification of firearms and ammunition within complex inter-related legislation.
The definition of a "firearm" is "a lethal barrelled weapon of any description from which any shot, bullet or other missile can be discharged". Although there is no legal definition of lethality it has been accepted that a commercially made 'gun', in full working order and discharging a commercial bulleted cartridge, would constitute a firearm. Problems do arise with the use of home-made guns, converted imitation or blank firing guns, re-activated/de-activated guns, and low powered air weapons. Some of these may be used in conjunction with home-made ammunition, sometimes made up of a blank cartridge and a separate missile such as a ball bearing or large size lead shot. Because these home-made, converted or re-activated guns are not engineered to the fine tolerances of commercially made guns and likewise for ammunition then the efficiency with which they discharge missiles cannot be presumed to be at a lethal level.
To make a sound judgement on the lethal potential of a gun and ammunition combination then, wherever possible, the velocity of a discharged missile or the depth of penetration of the missile into a tissue simulant should be measured. A direct comparison should then be made with the known lethal properties of commercially made firearm/ammunition combinations measured in the same way.
A similar approach is used for air weapons where at least some assistance is given in legislation for the minimum levels of pellet kinetic energy at which an air pistol or air gun become Section 1 firearms, i.e. air pistols at 6ft lbs and air guns other than air pistols at 12ft lbs. However, practical experience has shown that air weapons are capable of causing lethal wounds at below 6ft lbs. The minimum values of kinetic energy known to have caused fatal wounds are 3.7ft lbs with a .177 inch air rifle and 4.1ft lbs with a .22 inch air rifle. There have been at least eighteen (18) deaths in the UK caused by air weapons where the values of kinetic energy fall between 3.7 and 11.9ft lbs. These, therefore, can also be classified as lethal barrelled weapons.
Many years of collecting data from casework submitted to the Forensic Science Service enabled me to create a large database of deaths, wounds, and damage caused by air weapons of different makes, types and calibre. This type of information was available to other firearms examiners within the Forensic Science Service but the ‘new providers’ may take years to build it up.
M D Fletcher 15th September 2011