Part 3: Don Caswell covers targeting the hilum region for clean kills
The heart shot has been the goal of hunters since antiquity. Our ancestors needed to kill their medium-sized prey quickly, before it attracted the attention of major predators and was stolen by them. When tackling huge, dangerous game like mammoths and rhinos, the faster it was killed the less the risk of injury and death to the human hunters. For those using spears and arrows, the heart offered the best option for a fast kill.
That held true, right through into the age of firearms. Muzzleloaders, then more sophisticated black power rifles, threw heavy lead projectiles at low speeds. The late 1800s, just a few years before the turn of the 20th century, saw the advent of modern smokeless cartridges with smaller diameter and lighter weight projectiles. Smokeless propellants delivered much higher projectile velocities than had ever been achievable with black powder.
The much higher velocities revealed something that had been unknown to hunters up until then. Suddenly it was not just a case of drilling a hole through the prey with a heavy slug, but also the shock from the impact of high velocity projectiles. Projectile shock added a potent new effect into hunting that was keenly grasped by hunters but was poorly understood initially.
A good example of that was the controversy that arose in the 1930s when some prominent hunters began using the new .220 Swift on red deer stags loaded with, by modern standards, inadequate 50-grain soft-points. Spectacular instant kills were reported and it seemed that this new high velocity shock delivered tremendous killing power even for light bullet weight.
As more hunters started using the .220 Swift a different story emerged but one of utter failure unless perfect bullet placement was made. These days, of course, there is much better understanding of high velocity bullet shock and it remains the cornerstone to modern hunting. The .220 Swift, and calibres like it, have found their proper niche in long-range varmint shooting.
The shock delivered by the impact of a high velocity expanding projectile can be separated into two components. Hydraulic shock occurs in a narrow cone shape ahead of the entering projectile. It is hydraulic shock that creates the wound channel through the target animal. The higher the bullet weight and velocity, the greater the hydraulic shock and wound channel.
Hydrostatic shock, on the other hand, radiates out in all directions from the projectile impact. Hydrostatic shock can disrupt and even destroy major portions of the animal’s central nervous system that are well removed from the region of the bullet’s wound channel. Hydrostatic shock is the result of high velocity and the bullet’s construction, rather than weight, as it delivers fast expansion and dissipation of the kinetic energy of the impacting projectile. It was the hydrostatic shock of the .220 Swift that caused its spectacular instant kills on large deer.
Extensive studies reported from overseas indicate that once the terminal velocity of the projectile falls below about 2400fps, the hydrostatic shock greatly reduces. For modern hunting calibres with muzzle velocities around 3000fps this implies a range limit of about 200-250m, in order to retain large hydrostatic shock. This is a really important point to note for those folks who like to shoot their game out to extreme ranges.
Softer, faster expanding projectiles, or premium controlled expansion projectiles, would seem to be in order to maximise hydrostatic shock for long-range hunters. For hunters using popular calibres in the range .243 to .338, the key point is that at longer range you need heavier projectiles in the smaller calibres and rely more on hydraulic shock. If you want to keep significant hydrostatic shock at longer range, then go to a larger calibre. The topic of bullet construction and velocity is endless and books have been written about it, so I will leave that one right there.
The chest shot is the target for hunters of medium to large-sized animals. I consider head and neck shots as only viable at close range and even then, they can be problematic. The chest offers three zones for delivering a fatal shot – the lungs, heart and hilar. At closer ranges, there can be significant hydrostatic shock with a lung shot. There is not much resistance to the bullet in a lung shot and exit wounds are to be expected, and preferred.
As the range increases, and hydrostatic shock decreases, a lung shot does not reliably produce the emphatic kill desired. The heart is low down in the chest and shielded to some degree by the top of the leg. A well-placed heart shot cannot be guaranteed to drop the animal on the spot. Often, with a heart shot, the animal will perform a short sprint. The wound is a fatal one, but the animal can sometimes sprint 50 or more metres in its final dash for a few seconds. Over the years I have learned to favour the hilar, or high shoulder, shot as the preferred aiming point on medium and large game. If that shot option is not immediately available, for whatever reason, then just wait for the opportunity.
The high shoulder shot is, of course, no secret and has been well documented by lots of other hunting writers. YouTube has any number of videos about that. It is sometimes known as the hilar shot because the hilum region of the lungs is where the bronchi, major arteries, veins and many nerves are clustered.
Various nerves branch out from the vertebra of the neck, running off to the muscles and organs of the chest. The hilar target zone is larger than that for a specific heart shot and offers more margin for error on the part of the shooter. A low shot will strike the heart, a forward shot will take out major blood vessels, a rear shot will take the lungs and a high shot will blitz the nervous system and blood vessels.
An extra high shot will strike the spine for a similar devastation of the nervous system. With an adequate calibre and a suitable projectile, placing a shot through the shoulder blade hits like a thunderbolt.
For a lighter calibre and projectile, a shot into the centre of the hilar zone is also devastating. A shot, with plenty of hydrostatic shock, placed into the hilar region will most times produce an instantaneous and emphatic result. That is precisely what us hunters are looking for.