Part One Terminal Ballistics
Choices for the Big Game Hunter
Hunters today have more choices than ever when selecting a hunting firearm. Ammunition manufacturers are marketing a larger assortment of ammunition now, than anytime in the history of metallic cartridges. With so many excellent choices hunters should have no trouble finding the perfect rifle for their hunting needs. Choices, however, often cause more confusion, and create more problems than they solve. Choosing just the right weapon for game and hunting terrain can be very bewildering for the hunter with little experience in such matters. Some calibers are considered appropriate for types, and sizes of game, while others are not. Hunting terrain and distances are also factors that should be considered.
Taking part in hunting conversations usually reveals a hunter's level of experience. These discussions reveal the beginner to the average hunter who in turn becomes known to the experience hunter, who may learn he does not have all the answers. We intend this book to increase all hunters' knowledge of their cartridge and firearm. To allow all hunters to make better choices when selecting hunting firearms and ammunition for the big game, they hunt. We readily admit this book will not make anyone a better hunter. Still, it will greatly improve the chances of the hunter being successful once the hunting stops and the shooting begins.
Recommendations regarding proper bullets for specific size game animals are based on a computer game model. This computer game model consists of 917 big game animals taken over a period of almost thirty years. My hunting parties harvested much of the game in the game model. Recently, we asked hunters whom we consider responsible, to submit all game for which they have complete records, so that we might increase the size of our game model. Presently we have fifty-six hunters represented in the game model.
All game animals react differently when struck by a bullet. With a game model this large, the computer can predict and recommend average reactions with a degree of precision.
Many hunters believe ballistic tables published by ammunition manufacturers are completely accurate. They think if the published data states their 180 grain 30-06 ammunition is moving at 2700 fps (feet per second) at the muzzle that means every bullet from their rifle is traveling at that speed. This is of course, not true. Muzzle velocities not only vary greatly from one rifle to another, but also from one shot to the next in the same rifle.
Although muzzle velocities can vary greatly, ballistic tables are often used to compare various calibers for power, speed, and trajectories down range. Ballistic tables can easily be in error by more than + or -5%. This means the 180 grain bullet from your 30-06 could be traveling, on average any speed from 2565 to 2835 fps. This speed could vary, depending on ammunition consistency, twenty to thirty feet per second with each shot. Velocities could drop another 200 feet per second should the rifle barrel be shorter than specified in the ballistic tables. Ballistic variables are considered acceptable by all serious hunters and shooters and are little, if any, more accurate than our game model data. Learning to recognize which bullets are better for use on heavier game will increase the hunter's ability to stop game quicker. Those willing to learn more of their ammunition and firearm can gain much respect.
Understanding bullet behavior and factors that govern their effective use on game is essential. Bullets are made for a variety of targets. Our interests are mainly with those designated as hunting bullets. We can divide bullets into two groups within this category.
Conventional bullets are lead bullets with a copper jacket that is open at the point to expose the lead core. We believe these bullets to have a useful velocity range. This velocity range is limited on the high velocity end by over expansion (bullet blowup), and on the low velocity end by under expansion (no mushroom).
Expansion and penetration are the key factors governing conventional bullets' ability to stop game quickly. The velocity ranges of hunting bullets vary with construction and mass densities. Mass density is the real weight of the bullet.
Power by Case Size
Factory loaded ammunition does not show the proper order of a cartridge's overall potential, with regard to knockdown power. This is largely due to the overwhelming popularity of some cartridges. These move popular cartridges are often loaded with much heavier bullets than some which are less known. The heavier bullets loaded into popular cartridges such as the 30-06 Springfield, 30-30, and 270 Winchester, result in many of these cartridges being rated higher on the total power list than they would be should all cartridges be loaded equally, with maximum weight bullets. The case size power list below places most all presently available cartridge cases, used by North American Hunters, in proper order for total knock down power, with regard to Bullet diameter, case capacity, and pressure ratings as specified by our Case Size Formula.
The Case Size Formula is . . . cup Pressure x case capacity x bullet diameter / 1000.
Let's try a couple to see how this works. The 30-06 case has a case capacity of 69 grains of water, a pressure rating of 50,000 cup, and a bullet diameter of .308 inches. With the calculator we multiply 50000 (cup) x 69 (case capacity) = 3,450,000 x .308 (bullet diameter) = 1,062,600 divided by 1000 = 1063.
Let's compare this with the 284 Winchester case. We have 54,000 (cup) x 66 (case capacity) = 3,564,000 x .284 (bullet diameter = 1,012,176) / 1000 = 1012. The formula shows that the 284 Winchester is larger, when only case capacity and pressure are considered, but that the 30-06 becomes the larger, due to its ability to handle larger diameter bullets.
Numbers in the millions are rather large for me to contemplate so I have divided them by 1,000 for our data. Cartridge case overall size in our data, will be determined by us of this formula, and will be listed under Case Size Formula #, starting with the largest and most powerful cartridge.
The following includes: Rating # Total Power, Cartridge Case Name, Case Size Formula #, and Factory Load Power Rating #, listed respectively.
#1 - Nitro Express - 3416 - #4
#2 - 460 Weatherby Magnum - 3287 - #1
#3 - 416 Weatherby Magnum - 2942 - #3
#4 - 378 Weatherby Magnum - 2594 - #8
#5 - 416 Rigby - 2527 - #6
#6 - 416 Remington Magnum - 2269 - #5
#7 - 458 Remington Magnum - 2257 - #2
#8 - 375 H & H Magnum - 1868 - #9
#9 - 340 Weatherby Magnum - 1788 - #7
#10 -8-mm Remington Magnum - 1709 - #14
#11 -300 Weatherby Magnum - 1663 - #10
#12 -338 Winchester Magnum - 1551 - #11
#13 -7-mm STW - 1549 - #35
#14 - 300 Winchester Magnum - 1464 - #13
#15 - 300 H & H Magnum - 1430 - #24
#16 - 350 Remington Magnum - 1347- #36
#17 - 358 Whelen - 1303 - #17
#18 - 7-mm Weatherby Magnum -1283 - #15
#19 - 270 Weatherby Magnum - 1252 - #20
#20 - 444 Marlin - 1249