Meet Dr Chris Shepherd

Emily Collins

Ballistics is the science of the propulsion, flight, and impact of projectiles. It has a range of applications, including informing crime scene investigations, improving wound care and helping us design safer buildings. As an expert in the field, Dr Chris Shepherd, Director of Studies in the School of Chemistry and Forensic Science, has experience in all of these areas. Alongside delivering the number one forensics course in the UK, he is working with local and international partners to advance our understanding of ballistics for the greater good. 

How did you come to research ballistics at Kent? 

I’ve always been interested in forensic science so after studying an undergraduate degree in Biochemistry with Molecular Biology and Biotechnology, I pursued a Master’s in Forensic Engineering and Science. That’s where I learned about the engineering side of forensics, including weapon systems, firearms and explosive effects. Despite coming from a military family, I never thought I’d go into anything related to firearms, but my MSc dissertation worked on improving firearms investigation processes and then I studied for a PhD looking at the effects of explosive fragments on the human body from an injury prediction and treatment point of view. I wish I didn’t have to do this research and it’s something which would not exist in a perfect world. But it does, so I approach it as a means of helping people. 

Why study the impact of projectiles on the body? 

Different projectiles behave in very different ways as they enter and progress through the body. Even when using complex calculations and cutting edge computational modelling, the wounding effects are extremely hard to predict accurately because every situation and every person’s body is different. This is the constant frustration in my world – there is no perfect formula! This is why I do empirical testing, attempting to replicate the effects of wounding on the human body in consistent and ethical ways, building an understanding of how different projectiles might behave in the body and how this might feed into the wound created. This is in the hope of uncovering key information that can help medical professionals understand what they might be presented with if a certain projectile is involved in a projectile-related injury.  

What techniques do you use for this? 

I first specialised in understanding the extent of wounding and injury prediction during my PhD. In particular, I was looking at how we carry out experimental work and simulate the human body in a scenario where an explosive device is detonated. I now use a lot of biological simulants, such as gels and other synthetic materials to simulate different parts of the body, including soft tissue and bone. Understanding how these materials behave when they’re impacted by projectiles is a really important part of my work as it can lead to the development of new ones while helping us understand the wounding effects of different types of projectiles. CT scanning can also be really useful in my work as it gives a clear 3D picture of the extent of fragmentation in a wound and I have used it successfully to understand head trauma in my ballistics work.  

This summer, we’re so excited to be opening a new experimental ballistics facility here at the University’s Canterbury campus which will add to our unique portfolio of specialist forensics facilities. As well as using the facility for research and teaching, we plan to extend its use to external organisations, so I’m happy to be contacted by those with a ballistics testing need.  

Can you give an example of how your research has helped improve wound care? 

One thing that I’ve noticed from examining the path that bullets take through gels is that when a bullet or a projectile goes into the body, it results in ‘temporary cavitation’, where the body tissues are forced sideways and a cavity opens up inside the soft tissues of the body, only for it to close very quickly. This action can suck the projectile back towards the wound opening from the maximum point it has reached inside the body. This would be very difficult to detect without a CT scan but it’s important for medics to be aware of so that they know to remove the damaged tissue beyond where they find the bullet, as well as directly around it. This slight change of approach can help reduce the risk of the wound becoming infected, given how dirty and contaminated bullets and fragments can be. 

To what extent can ballistics be used to help solve a crime? 

Recently, I’ve supervised a PhD student based in Sri Lanka who has been researching bullet ricochets. Understanding how bullets behave within a crime scene can help us understand their wounding effects after they’ve hit, and potentially been damaged by, something else. If we find marks in the crime scene suggesting that a ricochet has occurred, we can recreate those marks in a controlled environment to hopefully work out the type of bullet used and the angle from which the ricochet mark was created, enabling us to predict the bullet trajectory and possibly where it was fired from.

If we have a bullet from a crime scene, we can also start to try and relate it back to a particular firearm by using what we call comparison microscopy. At Kent, we have a cutting edge comparison microscope that allows us to do that, so if we have a weapon that we think was involved in a shooting, we can fire that weapon with the same type of ammunition that we’ve found at the scene, collect the test bullet and compare the individual characteristics (microscopic markings that form a kind of ‘ballistic fingerprint’) with those of the bullet we found from the actual shooting to see if they suggest the weapon fired the bullet from the scene. 

Tell us more about this ‘ballistic fingerprint’? 

Over time, each firearm develops its own unique interior, evolving from its factory state (just like we change as we age).  As the bullet goes over the surfaces inside the weapon, that unique profile gets imprinted on the bullet. There are certain markings, called class characteristics, which relate to a range of firearms and others (individual characteristics) which are specific to individual firearms. By studying these, we can possibly rule out a particular weapon from an investigation or suggest it’s highly likely that it was involved. This is just one of the many exciting topics we teach in our forensic science courses at Kent.  

Dr Chris Shepherd is a Senior Fellow of the Higher Education Academy and a professional member of the Chartered Society of Forensic Sciences. He has published in a number of high-profile forensics journals and has advised on criminal cases and TV shows. Chris is open to being featured in print, on TV and radio.