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exbiologist's picture
Location: Colorado
Joined: 09/19/2008
Posts: 2397
Terminal Balllistics Study

I've been thinking about ways to predict, model and or quantify terminal performance on game. I'm not much of a statistician, nor am I great with test designs, and I'd like some input. I was thinking about utilizing a survey, with some very specific questions regarding entrance and exit locations, bullet impact velocity, and a GPS measured distance travelled, maybe rifling twist, not sure what other categories, but maybe you can help me with that.
Just a guess, but it would probably take a hell of a lot of input to get anything meaningful or statistically significant from this. Something on the order of several thousand samples.
Just figuring out what questions to ask to narrow down all the variables is pretty daunting though.
Among the things you'd need to specify:

Entrance and exit location-if sticking with broadside and quartering shots, I think you'd need a way to break up the torso into sectors based on horizontal distance betwen the point of shoulder and last rib and vertical distance between the bottom of chest and top of whiters.
Bones hit-you'd probably have to specify whether ribs, humerous, scapula or spine was hit on entrance and exit.
Also might have to specify whether the heart was hit.

Animal variables-while mammals all have roughly the same skeletal structures, there are probably constitutional differences among species, sex, and size which would affect terminal performance. Rather than required animals to be weighed, you might be able to get away with a chest girth measurement.

Projectile variables- Specifying Make, model, weight and caliber of the bullet probably isn't enough. Twist might matter, velocity will almost certainly matter, so knowing the exact distance to the animal will matter, as will knowing the muzzle velocity, which would likely rule out factory load users who haven't chronographed the load in their own rifle because, hey, maybe 100 fps does make a statistical difference?
Ideally, you'd be able to lump a lot of bullets into similar categories, like the bonded, tipped boattails, the tipped monometals, partition-style, etc to increase your bullet sample sizes. But due to jacket variations, bonding processes, material differences, that's probably not possible.

Shot reaction: don't how else to measure effectiveness other than to measure distance travelled from site of impact. And even then, how are you going to do that? A GPS measured distance will give a straight line distance, but can't account for any zig-zagging (which they don't do much of anyway in my experience.)

What else am I missing? Obviously, pulling off a meaningful study would be difficult due to the sampling size and variables involved. But I'm not certain this is impossible to pull off.

bitmasher's picture
Location: Colorado
Joined: 02/27/2002
Posts: 2974
Re: Terminal Balllistics Study

Hmmm, I think your results are going to be skewed, because the only ones answering will be those that recovered the game. What about those that hit the game somewhere but was not recovered. I suppose you could put a filter up and say that your only interested in those that hit the main torso. But again there will be some of those that are not recovered and are probably statistically significant.

I think terminal performance is pretty well defined by bullet weight retention, bullet expansion, and exterior ballistics.

Don Fischer's picture
Location: Antelope, Ore
Joined: 03/24/2005
Posts: 3206
Re: Terminal Balllistics Study

I'm not sure where your going with this but this might help. P.O. Ackley volume II; "Gun shot wounds" x Col Frank T. Chanberlin. If I remember these test's were done at Edgewood Ansenal and were conducted to help in treating service men with gun shot wounds. Cadaver's and sedated hogs were usen in the study. I read it years ago and as I recall it was intresting.

WesternHunter's picture
Joined: 05/05/2006
Posts: 2374
Re: Terminal Balllistics Study

I think there are just too many factors involved to get any very reliable consistent data. Heck even taking 6 white-tails from the same area, the same age, same sex, same size, same day, use the same load from the same rifle and same distance, hit em in the same spot, and you'll likely get at least 5 different results. Terminal ballistic performance is put out there by the bullet makers and the ammunition makers for mainly one reason - to make you think you need their new bullet each season and to sell their new products to you. Meanwhile those same old fashioned out-dated standard jacketed soft points continue to perform very well for hunters on most biggame around the world every year. I say if your worried about performance then just stick with a .30-06 in an appropriate bullet weight for the game you are pursuing, and you should be able to take about any biggame animal in the world with great performance :\:D/ Still I think running tests like you describe would be cool and interesting to see the results.

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