The Hornady Ballistics site http://www.hornady.com/ballistics-resource/ballistics-calculator can calculate some valuable information about your hunting bullet but it does not determine the game it can kill at the velocity/energies listed. I have researched tools to aid in finding the Optimal Game Weight for a given load and distance. I have last month published articles on Sectional Density and other methods to quantify the game size/weight.

In the book, Big Game Rifles and Cartridges, the author Edward Matunas presented his famous formula: Where Velocity cubed (V³) multiplied times bullet weight squared (W²) was further multiplied by 1.5 times 10 to the minus 12th. The formula was put forth again in the Second Edition of “Applied Ballistics” by Bryan Litz

Optimal Game Weight (OGW) = V³ x W² x 1.5 x 10¯¹²

For those of you who have a XL spreadsheet and want to play with this formula, you can do so. What is not covered in this formula is the effect of mushrooming of a bullet as it penetrates and on its killing effects. Or the effect of less than full penetration if the bullet separates on entry. The value of a large wound channel and the value of hydro-static shock, on vitals is absent, which are key elements not included but the fundamentals of velocity, bullet weight and momentum.

I played with add on’s to the formula but without specifics; they were “what if” games. What if the bullet mushrooms to 1.5 times the size of the bullet diameter which often occurs in hunting bullets? What if the bullet does not fully penetrate? What then?

In order for this formula above to work well, the bullet must be constructed so that it will not come apart in the animal and that it will mushroom creating a large wound channel. I like my bullets to penetrate with ample power and hydro-static shock so there is an obvious blood trail. Further that Sectional Density is considered in choosing a bullet where SD= Weight of Bullet in grains (converted to pounds) and divided by the Diameter Squared.

For deer the ideal SD is around 2.5 and elk above 2.5 and Moose 3.0 or higher.

http://www.beartoothbullets.com/rescources/calculators/php/density.htm

After that the calculation should be; How far can I shoot the animal and ensure a clean kill remembering the need for mushroom and hydro-static shock. Some bullet designers have lead bullets that mushroom at 2000 fps and that hydro-static shock occurs s in the same speed range or faster.

Even Chuck Hawkes has a section on this; http://www.chuckhawks.com/game_range_caliber.htm

Just remember, a small marginal bullet in the vitals is better that an more than adequate big bullet in the big toe especially if the animal wants to seek retribution on the hunter.

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Great stuff to talk about after dinner at the campfire. What your skill level is, the game you are hunting, the distances you expect to see and shoot at game play a part in what cartridge and bullet you use to hunt with and kill game.

It has been my experience and those of millions of veteran hunters that accurate bullet placement is the beginning discussion of stopping power. Accordingly, without good bullet placement in a vital area the discussion simply evaporates into the smoke rising from the campfire. First things first, shoot accurately!

Having said that it is important to understand the elements of Terminal Ballistics when discussing big game such as large northern whitetail deer, bear, bison,and moose. If a bullet has sufficient energy to damage vital organs it will kill cleanly, some cartridges do this better than others.  I believe it is better to err on a moderately larger rifle cartridge if you can shoot it accurately especially if you are a hand-loader.

Cartridges that are adequate in stopping power for deer abound. I believe the 6 mm/ .243 is an excellent starting place as long as bullet construction and weight are designed for deer where the shot is broadside and distances are known. Clean kills for this caliber are well documented to 300 yards with a 90 to 105 grain bullet and recoil is very low. Those who are veterans and can handle recoil better may prefer a cartridge that has more power/kinetic energy and bullet weight such as the .308 Winchester, 7mm08,  .270 Winchester, and the 30-06 Springfield. Most of these do well in the 120 grain to 180 grain weights. Jack O’Connor created worldwide fame of the .270 Winchester with a 130 grain bullet because it had moderate recoil and packed tremendous downrange energy but Jack hunted mostly out west where trees and branches were not in the way. Still the .270 Winchester and the 30-06 corner the market for most adult hunters. Those of us that hunt in brushy areas may want a heavier bullet that deflects less in brush such as the 35 Remington,444 Marlin or .375 Winchester for quick examples. The .338-06 and .338 Marlin are great for hunting game in brush too but can reach out when needed. Of Course if you hand-load you can make some big bore rifles shoot slower or faster as there are loads and bullet combo’s that can achieve this, like my .375 Ruger which replicates the .375 Winchester and the old 38-55 Winchester when hand loaded for deer and bear. At full power the .375 Ruger shines for Bison and Moose. There are time when hunters may want more stopping power for the game they are hunting because either the game is potentially dangerous at close quarters or of such size that they want to anchor the animal right there or both. I anchored this 800 lb small Bison with one shot from my M77 Hawkeye African in .375 Ruger with a single 260 grain Nosler AccuBond traveling at 2600 fps.

The bullet entered the last rib and drove forward through the chest cavity wrecking the heart and lungs and exited the far shoulder. The bull collapsed in just a few steps.  Stopping Power is a nice ally in that situation as there was ample hydro-static shock and penetration.

Where “stopping power” by definition seems to have derived its roots is the effect of “hydro-static shock” effect on blood and tissue, so fast and severe that it can rupture tissue far away.  It is not just speed of the projectile that  produces the effect of “Stopping the animal in its tracks”  it is a combination of speed and penetration that does it.  Penetration has a lot to do with bullet speed and weight, its cross sectional area, shape and momentum.

A bullet that travels faster than the speed of sound for example carries with it a bow wave as it travels.

Bow shock wave image from Wikipedia: http://en.wikipedia.org/wiki/Bullet_bow_shockwave

I believe that this wave may be responsible to a large degree for hydro-static shock that can damage tissue and organs not near the wound channel. In some cases via hydraulic effects in arteries this wave can induce shock as far away as the brain especially if speed is sufficient with penetration.   The shock wave in general disrupts tissue to such a degree as to turn it to a jelly like mass. The liver can be an organ that is inedible if it encounters hydro-static shock as it has happened to me.

The cross sectional area and shape of the bullet face and bullet weight known as Sectional Density (SD) contribute to penetration and momentum that continue to provide damage to vital organs

From Wikipedia:

“Sectional density is the ratio of an object’s mass to its cross-sectional area. It conveys how well an object’s mass is distributed (by its shape) to overcome resistance. For illustration, a needle can penetrate a target medium with less force than a coin of the same mass.

Sectional density is often used in gun ballistics where sectional density is the ratio of a projectile weight, to its diameter. Sectional density is important to understand when selecting a cartridge bullet combo.”

Here is more on its value from Chuck Hawkes http://www.chuckhawks.com/sd.htm

To find the SD of your rifle bullets: http://www.beartoothbullets.com/rescources/calculators/php/density.htm?

I found the SD for the 90 grain .243’s I am testing to be very adequate for deer.

Further there is discussion of the Controlled eXpansion (CXP) Performance Rating System developed by Winchester is here. http://www.chuckhawks.com/cxp.htm

Bullet Construction can be Lead, Copper sheathed spitzer and round nose, Partition/A-frame, solid gilding metal that can flare like the Barnes and Nosler E-Tips. Note: a round nose bullet or flat point must use more energy up front to enter the skin and tissue and provide more of this shock wave value at entry.

As an example all Dangerous Game bullets are round nosed or flat-point of sufficient SD and mass that it is like getting hit with a fast moving barn door instead of a knife blade.

Further that if we assume that a higher SD bullet that grows in diameter (mushrooms)  as it penetrates tissue, providing a larger wound channel.

If you skipped the Chuck Hawkes articles go back and read them. There is a lot of Campfire Fodder there. Good Hunting!©

As many of my close hunting friends know, I am a Bowman as much as a Rifleman. I have spent many years shooting a recurve and longbow in my youth but was never better than average with them despite winning Traditional Trophies with them. When I picked up the Compound Bow my skill level skyrocketed. It was not uncommon for me to regularly win 3D shoot trophies as you can see above my workbench.

In my Book African Safari – Rifle and Bow and Arrow I was able to cleanly kill a Gemsbok and Red Hartebeest a culmination of my shooting skill and patience in a blind. Of the two I am most pleased with the Gemsbok. I was shooting a High Country Sniper Bow back then set at 74 pounds. I had to set it lower to hunt with. I competed with it set at 82 pounds. The reason I lowered the poundage was because the roll-over of the cams at 82 pounds was too jerky with too much movement. At 74 pounds the rollover was controlled. Both kills were full penetration and exit making tracking a no brainer. If you get a chance to check out  my e-book in the header above, you won’t be disappointed.

I love rifles just a much as my bow and have dedicated time to Rifles,Pistols and the Second Amendment especially in these times where the leftists in our government want to take those rights away. I enjoy hunting and shooting my pistols and rifles and will work support them forever.