If i shoot a moose whit a 375 H/H do the hole get bigger in the moose if i shoot the same bullet whit a 378 Weatherby, because the 378 wby has more energy...?

Some buddy who knows...

George

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Shoot straight, shoot often, but by all means, use enough gun!

If you are interested in terminal ballistics, Harald's site is the best I know of: http://ulfhere.freeyellow.com/ballistics/wounding.html HTH, Dutch.

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Originally posted by Dutch:
In general, the faster the bullet, the quicker that tissue has to get out of the way of the bullet, the larger the "cavitation" caused. Some of this cavity is temporary.

If you are interested in terminal ballistics, Harald's site is the best I know of: http://ulfhere.freeyellow.com/ballistics/wounding.html HTH, Dutch.

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Ditto on the website Dutch. Bullet placement, penetration, and cavitation. IMHO the information in this web-link is clearly the best and most objective terminal ballistics studies done to date. Many myths were laid to rest.

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BH1

"Did you use excessive force?---I HIT IT WITH EVERYTHING I HAD!

I found the website interesting, but I also have found some of his conclusion do not fit with personal experiences.

Todd E

If you feel you can contribute better, more objective information than Harald, please accept my invitation to present it. JMO, Dutch.

To address the question specifically, according to Cranz' Law, a penetrator will cavitate a volume proportional to its kinetic energy. Now, this assumes a rigid penetrator and a perfectly plastic target, neither of which are found in the real world. The resistive forces of fluids are typically nonlinear functions of the penetration velocity (just like air drag). All of this means that "bigger" may not be much bigger and certainly not better. In general though, more KE will create a larger diameter wound for any given bullet while giving similar penetration.

I don't like to be confrontational or accusatory, but this is about the 20th thread that Overkill has started on the general theme of "How do I make a hole in a moose that I can park my Volvo inside?". I don't wish to encourage a morbid fascination or make myself a fool for insincere questions. I doubt the sincerity of Overkill. Perhaps I judge hastily. But I don't think so. I only responded to this for anyone out there who is reading this with sincere interest, to say what I am saying now, and because my name came up. I admit to having a morbid fascination with each new permutation of Overkill's moose questions. So I looked. Mea culpa.

If i shoot a moose whit a 577 T-REX 750 grains Hawk bullet at 2500 f/s. And shoot the moose in the shoulder and hit bone at 50 yards.

Then the soft Hawk bullet would expand to a very big diameter in the moose and leave much energy.

Then the hole would get big

Have i right...? some buddy who knows...?

"This is the most insightful thing I have ever read I have ever read on shooting. He clearly understands this better than nearly anyone and has put it on paper better than anyone that I know of."

My hunting "buddy" is not confused by anything physical. He knows!

"This is the most insightful thing I have ever read on shooting. He clearly understands this better than nearly anyone and has put it on paper better than anyone that I know of."

My hunting "buddy" is not confused by anything physical. He knows!

[This message has been edited by Don Martin29 (edited 01-27-2002).]

I am still trying to absorb the site before I go off half cocked.

There are sites on the "Scientific Method" and the "Socratic Method" some of use should learn these before we step into the ring.

I did not mean to sound negative. I only was trying to instill in these guys that the information on you site, while it appears very objective, we do not know all the particulars of the test procedure.

In my experience the big bore rifles with soft points will create large wound channels even if bones are not struck. The impact area and the resistance encountered by the bullet while it is attempting to puncture through the flesh seems to be enough to produce significant upsetting of the bullet itself. This phenomena has not manifested itself though with the 416 and smaller calibers to the same extent.

Another observation is that the diameter of the bullet seems to be directly proportional to the diameter of the wound channel. The spire point 30 cal will not generate much more of a wound channel than a 50 cal solid round nose. The 30 cal may upset to a total diameter of .45 - .5 inches while the 50 cal does not expand at all. The tip geometry of an expanded bullet also is close to a that of the round nose so go figure.

Now if the big bore, say 50 cal, soft point hits bone two things tend to happen.
1.) Extreme expansion i.e. the bullet pancakes and penetration stops.

2.) Extreme expansion i.e. the bullet pancakes and the bullet follow the path of least resistance rotates and continues like a "saucer" producing a dramatically smaller wound channel.

Todd E

You wrote: "In my experience the big bore rifles with soft points will create large wound channels even if bones are not struck."

I agree.

"The impact area and the resistance encountered by the bullet while it is attempting to puncture through the flesh seems to be enough to produce significant upsetting of the bullet itself. This phenomena has not manifested itself though with the 416 and smaller calibers to the same extent."

I suspect that this may be due to the fact that jacket thickness doesn't always increase proportionately with .458s and larger and also they have a larger soft nose to exert stress on the inside of the jacket. I think it varies a lot but I have had a sense of this too.

You further wrote: "Another observation is that the diameter of the bullet seems to be directly proportional to the diameter of the wound channel. The spire point 30 cal will not generate much more of a wound channel than a 50 cal solid round nose. The 30 cal may upset to a total diameter of .45 - .5 inches while the 50 cal does not expand at all. The tip geometry of an expanded bullet also is close to a that of the round nose so go figure."

The wound diameter seems to be driven by three things: velocity, bullet diameter and nose shape. Various combinations will produce similar wounds, but in general (since velocities tend to run in the same range and since nose shapes tend to be similar, especially after expansion) the wound is proportional to bullet diameter. Here, too, I think we agree.

There is a lot of hand waving on my site and not many hard answers, I know. I included my ballistic tests as a practical way of demonstrating just how difficult it is to make any valid generalizations. You don't have to look hard to find an exception. Probably I should simply post the Tate equations that I have been wrestling with to show how nasty the real problem can be.

The Tate equations describe the penetration of a homogeneous eroding cylindrical rod. To render this meaningful for any bullet we would have to first modify the model to account for the non-cylindrical bullet shape, which is mainly the part that deforms. Then, for most bullets we would have to account for the fact that the construction is not homogeneous (and the material properties vary?). Thirdly, we would need to introduce a coefficient of drag not found in Tate's equation that is a non-linear function of velocity. And last of all we need a way to describe the effect of different nose shapes in some normalized manner so it can be applied to any caliber. My first experiments with a relatively simple modified form of the Tate equation were disappointing. The behavior is approximately correct but the answers are not quite right.

Worst of all, the Tate equations do not describe the diameter of the hole and we care as much about that as we do about the depth. The do this correctly we have to get a model for the curling back of the jacket / petals and also the work hardening effect that occurs since this influences the velocity at which expansion stops. This is really the thing that stumps me. Even finite element codes don't do a great job of this kind of deformation. If we had enough test data we could cluge up some empirical fits that would work well enough for most classes of bullets, maybe correlated to some test case you could do in a bucket of water.

For now I just don't have the definitive answer to how brand XYZ bullet will behave at 2745 fps. I suppose this is a bit of an apology for why I talk around the subject but in the end I don't have something for you to take away that will tell you all you want to know.

I didn't ever think that we really disagreed. I can appreciate the complexity of the problem and effort required to mathematically model it.

My issue wasn't so much with anything you had posted on your site as those that read it and do not understand/appreciate the fundamental concepts that support the conclusions drawn. I was simply trying to get individuals to attempt to attain a greater knowledge of science. It didn't hurt that I was having a bad day either.

Todd E