I don’t know whether I can explain this concept in a short magazine article, but nothing ventured nothing confused.
Foot pounds (ft lbs) of energy is a fairly simple mathematical concept. The formula is very straightforward and you can look it up more quickly than I can write it down.
I will say that in the formula the bullet weight is not nearly so important to the final result as velocity. I will also tell you that the famous foot-pound is simply one pound of weight acting through one foot of distance, so 3,000 ft lbs is equivalent to 3,000 pounds acting through (or falling) one foot.
When we talk about impact energy of a specific cartridge foot-pounds is what we are talking about. In reality it is a very poor description of the possible result on game, particularly since the diameter (or caliber), of the bullet is not figured-in at all. Yet it is, in my opinion, the best way we have to quantify the impact power of a cartridge.
Other ways have been postulated, such as pounds feet, which Elmer Keith advocated. Unfortunately, those are not actual scientific, mathematical formulas, whereas foot-pounds is. However, over more than five decades of hunting, I have observed that pure energy is a very poor way to tell what effect a particular cartridge and bullet will have on game.
I first observed this phenomenon when I began hunting deer with a .25-06, way back in the early 1970s. I was told that the only way to go was with heavy 117- or 120-grain bullets. For a couple of years, I shot deer with these loads, which should have, according to the ft-lbs formula, flattened every deer I shot.
The actual result was much different. In fact, every deer I shot ran at least some distance, and some ran a long way, with a bullet through their lungs.
Then I bought a box of 100-grain bullets and loaded up a few at high velocity. The impact energy of the heavier bullets was practically identical to that of the lighter bullets, but the result on deer was very different. With the 100-grain bullets I seldom had to track a deer.
Then a game warden buddy of mine found some 220-grain .308 caliber solid bullets and loaded up a batch in his .30-06. He figured that if solid bullets were good for shooting elephants and Cape buffalo, they would be great for shooting does without wasting a lot of meat.
Strangely enough, the 220-grain solid bullets simply would not put a deer down without hitting the shoulder, neck, or spine. A 90-pound doe shot through the lungs with this heavy bullet would run completely out of sight. If the 220-grain bullets had so much impact energy, why did they perform so poorly on relatively small deer?
This led me to do some experimenting, and eventually led me to a conclusion and a phenomenon that I have observed throughout the years. Put as plainly as possible, when shooting game the caliber, structure, and shape of the bullet are more important than the paper ballistics.
For instance, if I am shooting deer with my .35 Whelen, a 200- or 225-grain bullet will give more instantaneous kills than 250-grain bullets. The reason is, I believe, that the heavier bullets are much more strongly constructed than the lighter ones.
This is because the heavy bullets are intended for use on larger, heavier game and do not begin to open up (mushroom) quickly enough in the small deer to transfer all that energy to the target. Instead of opening up and depositing all that energy in the animal, thus destroying a lot of tissue, they just make a small hole all the way through the deer—just like the 220-grain solids my game warden buddy was using.
Tissue destruction is what makes a cartridge effective, as long as the destruction is to vital organs. A bullet can have a million ft-lbs of impact energy, but be a poor killer if it cannot transfer that energy to the vital organs of the deer.
On the other hand, I have seen deer, even coyotes and bobcats, that also ran off after being shot with ultra-velocity cartridges such as the .22-250 and .17 Remington. Here, the culprit was not too strongly-constructed bullets, but bullets that were not tough enough to get to the vital organs. In these cases the bullets exploded after penetrating only a couple of inches, leaving a large, but not quickly fatal, surface wound.
This is why I preach choosing the right bullet for the game you are hunting. If you are going after brown bears, you should choose a heavy, tough bullet. If you are shooting varmints you should choose a light, highly frangible bullet.
For deer you should choose a bullet heavy and tough enough to get to and through the vitals, but not so tough that it will not open up and fail to destroy the vital organs. This means a bullet that is not meant for varmints or brown bears, but for deer. If you do this, then the kinetic energy packed in that bullet will cause the tissue destruction necessary for a quick kill.
By caliber, these are the bullets I generally choose for deer in non-magnum cartridges. I arrived at these choices after a whole lot of hunting:
.22 caliber—55- or 60-grain Nosler Partitions or 64-grain Nosler Bonded Performance*
.243 caliber—95-*or 100-grain Nosler Partitions
.257 caliber—100-grain Hornady or Speer soft points or 110-grain Nosler AccuBond*
6.5 caliber—129-grain Hornady SST, 130-grain Nosler AccuBond, or 120-grain Barnes TSX*
.270-caliber—130-grain Speer* or Sierra soft points
7mm caliber—130-grain Speer*, 139-grain Hornady, or 145-grain Speer soft points
.30 caliber—150-grain Sierra, Hornady, or Speer* soft points or the same bullets in 165 grains.
.35 caliber—225-grain Nosler AccuBond* or 225-grain Sierra Game King (In this caliber I loved the Nosler Ballistic Tip, but it is no longer made in the larger calibers. In the smaller calibers it is not tough enough for hunting deer.)
*Asterisk denotes current favorite.
Email Steve LaMascus at ContactUs@fishgame.com