When is a Shot Safe?

In the 1940's & 50's the American middle and upper classes happily built their homes in and around the inner city.  Close to the shopping, churches, cultural centers, and the factory or office workplace, America became an urban nation where the countryside belonged to the farmer.  At some point during the last 30 years however, the pronouncement went out that "would the last one out of the city please turn out the lights!"  More and more homes are popping up in rural areas across Indiana as people have come to appreciate the benefits of country living.  The old farmsteads once best used to produce cash crops and timber, are increasingly being broken up with lots sold to homebuilders.  This presents Indiana predator callers and varmint shooters with a background increasingly dotted with dwellings.  In many open agricultural areas where the shooter must sometimes anchor a coyote at two or three hundred yards, the weapon of choice will remain the centerfire varmint rifle.   In dealing with this situation an understanding of the behavior of high velocity projectiles is essential to the predator hunter who must decide when a shot is safe, or must be passed up.

I've always seen my own personal dilemma in this regard as a matter of bullet choice.  Since I shoot a .243 Winchester I have a full range of choices from  a tough heavy hunting bullet that is well contructed to a light frangible projectile that is supposed to fragment if you so much as look at it wrong.  It's well documented that high velocity bullets are capable of delivering the full spectrum of desired performance when they slam into living critters.  At one end of the spectrum, copper or cupro-nickel solids, partitions, or thick jacketed core bonded bullets are capable of properly mushrooming, retaining most of their mass and plowing through even the toughest bone and muscle with a controlled expansion.  On the other hand thin jacketed light-for-caliber frangible varmint exploding pills assure obliteration and fragmentation when striking even the smallest and thinnest skinned animals.  In recent years callers even have their choice of frangible or  very tough bullet construction  in the .224 calibers as the popularity of taking deer with the 22 centerfires has grown in states where it's legal. 

The ideal shot on a furbearing critter will enter, fragment, and not exit, leaving the animal ready for skinning.  In reality, high velocity frangibles that strike bone or happen to shoot-through can often turn a pelt into bloody shreds.  Use of a tough bullet that typically makes a small entrance hole and medium sized exit hole may be the answer in some cases, especially in the .243 which must find a repository for scads of excess energy at impact.  It would seem that a reasonable answer is to allow a shoot-through to carry the uneeded energy safely away from the pelt.  For my own calling, however, I have chosen frangibles for safety reasons.  This is based on the assumption that the frangible would fragment extensively upon striking the ground, thereby carrying little energy into the background and presenting a minimal hazard to property or persons several hundred yards away.  A larger, slower, well constructed hunting bullet it would seem, would likely expend less energy tearing itself apart upon striking the ground and be more apt to ricochet into the background carrying enough energy to continue downrange and possibly do harm.   This type of logical thinking is highly suspect, however, when it comes to high velocity rifle bullets, whose behavior often seems to defy logic.    I once shot through jugs of water placed in a line expecting to be able to recover the spent rifle bullets.  Certainly a projectile which I know to be capable of penetrating 8 inches of solid oak, or a 3/8 inch thick plate of mild steel, can survive collision with water jugs?  What I found in the water jugs was small lead fragments and pieces of jacket only.  In fact law enforcement ballistics labs cannot typically recover  rifle bullets fired at full velocity with conventional water filled recovery tanks.  Fragmentation when striking water necessitates the use of reduced loads or  better specialized stopping media to produce a useable recovery for barrel signature testing. 

So what becomes of our bullets downrange after they hit the dirt?  How far do our bullets go and  in what form?  Is a high velocity varmint bullet "done" after it strikes the ground?  To produce some answers to these questions (and give me another reason to play with my guns) I ran some "real world" tests.  To simulate a missed shot at a coyote in open country, shots were fired with my .243 Winchester, from the sitting position, at distance of 110 yards and allowed to strike the ground in a frozen cornfield.  Papered target boards were waiting behind the ground strikes to record any ricochets or high velocity fragments produced.  3/4 inch plywood was used as the target board with an additional piece of 3/4 inch pressboard  backing the target board.  In flat country this is probably the best "worse case scenario" possible, simulating a missed shot at a coyote or varmint that's most likely to produce a dangerous richochet.   

To shed some light on this we will first look at and measure some actual events to get a feel for what happens downrange.  Then we will use those results and a very basic ballistic model to follow a theoretical ricochet downrange to get a feel for the potential dangers.