Hunter aiming through his scope

Spomer on Shooting: Blood Trail Bullets


John Munnerly Submitted on 2015/11/19 at 8:24 am

The last two bucks I killed are both on the wall. I got lucky with both, one I really had to search for. Neither deer left any kind of a blood trail. I am shooting a .30-06 using 165-grain Remington Core-Lokt ammo. I felt the shots were good but with no blood trail I am wondering if I should be using other shells. I may need to aim further back for the front shoulder – that could have kept the shell from going through. Wanted your thoughts on the ammo.



Arky Submitted on 2015/11/10 at 2:47 pm | In reply to EsoxAC.

What type of ammo do you use for close range 40-80 yards? I’m looking for something that is fast expandable with a very pronounced blood trail?


Good letters about blood trails by readers John and Arky raise the perennial question about bullet performance. What is better, dumping all energy within the animal or punching through to create another hole for a potentially better blood trail?

Ron Spomer
Ron Spomer

First we must understand how deer/elk bullets work. There are three major types:

  1. Soft, Malleable Cup-And-Core Bullets

This includes bullets such as the Remington Core-Lokt, Winchester Power Point, Federal Soft Point, Hornady SST and Interlock, Speer Hot-Cor, Sierra Game King, and many more like them consist of a thin gilding metal jacket surrounding a lead core. This lead can be pure and very soft or hardened to varying degrees.

The thinner the jacket and softer the lead, the more the bullet will deform upon impact. Higher impact velocities also increase this deformation and can result in the jacket and lead separating. A “bonded” version of the cup-and-core welds the two metals to eliminate jacket separation. This increases retained weight of the bullet, which in turns maximizes penetration.

The ideal bullet “deformation” is commonly known as mushrooming. You want the bullet to expand slightly to increase the surface area that can then damage more tissue as it passes through the lungs, heart, liver, etc. The problem with expansion is that it increases friction, which decreases penetration. Depending on which muscles, bones and internal organs the bullet hits, a cup-and-core might flatten like a pancake and barely penetrate. It might mushroom perfectly and penetrate through to the offside skin. Less commonly it will punch completely through that skin.

  1. Frangible Bullets (Similar to Varmint bullets)

A variant of the cup-and-core is the frangible, varmint-type bullet designed to break into several fragments. These ideally “explode” in the thoracic cavity to do severe damage to heart and lungs. The concern is that they’ll break apart before entering the vital organs, resulting in a flesh wound. For this reason, frangible bullets are not legal in some states.

  1. “Controlled Expansion” Bullets

This means mushrooming is limited somehow and the integrity is preserved for maximum weight retention. Both these — controlled frontal surface area plus high weight retention — increases the chance the bullet will pass through the animal. Examples include hollow-nose, all-copper bullets such as Barnes TTSX, Nosler E-Tip, Hornady GMX, Winchester Power Core, Federal Trophy Copper, etc. Thick jackets and bonded, hard-lead cores are another way to minimize expansion and retain weight. So is adding a wall of jacket material across the center of the bullet (i.e. Nosler Partition, Swift A-Frame.)

Deer hunters are urged to think of their ammunition by these bullet types rather than by brand name, cartridge size, etc. The bullets do the damage and the right bullet, regardless which cartridge/powder charge launches it, can kill instantly, quickly, or slowly depending on not just where it lands, but how much it mushrooms and how far it penetrates.

As for exiting to create a blood trail or staying inside to dump all the energy, I argue for the punch through option. I say this after nearly 50 years of shooting literally hundreds of whitetails, mule deer, elk, pronghorns, caribou, moose, eland, kudu, oryx, etc., with every type of bullet and dozens of popular cartridges from .22-250 Rem. through .470 Nitro Express. Energy doesn’t kill. Blood loss does.

The only time you should expect any bullet to drop an animal in it tracks is when it strikes the central nervous system. Brain and neck/spine hits back to the front shoulders do this. Sometimes a heart or even a lung shot will drop a deer instantly, but not usually. Some say if the heart is pumping and blood pressure is maximized when the bullet strikes, the extra pressure does the trick. I’m not convinced, but it does seem to happen. Still, I don’t expect it to. I expect every chest shot deer to live for several seconds and usually run 20- to 100 yards. They have gone farther. It depends on how quickly the bullet damage reduces blood pressure and, thus, oxygenated blood from reaching the brain. That is what terminates game. Blood pressure drops, game gets dizzy, wobbles, falls. Starved of oxygen, the brain dies.

Finding the animal that runs before this brain death occurs is the key, and a “punch through” bullet can help. A bullet entrance hole is usually tiny and can seal shut. The exit wound is usually large because the bullet has expanded and often blown bone fragments out with it. The result is a large wound from which blood can flow freely.

Conclusion: If you want to increase your odds of finding a blood trail, use a heavy, controlled expansion bullet, either all-copper with hollow nose or bonded lead with thick jacket or partition type. Don’t worry about caliber or cartridge or rifle barrel length. Those are minor details compared to the type of bullet.

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One Response to “Spomer on Shooting: Blood Trail Bullets”

  1. Steve Reid

    Not critical info but the Core Lokt is one of the first of the “controlled expansion” bullets and still advertised as such.

    God Bless