# Thread: Terminal Energy & Ballistics

1. ## Terminal Energy & Ballistics

Say for example a Roe is shot from 200yds with a 150gn .308.
The round passes through the chest cavity striking a rib on entry & on exit.
Is there a formula for calculating the terminal energy residing within that round upon exit from the chest cavity?

2. You can easily work out what energy it has at 200 but I should imagine it would be quite difficult to know after its past through as the bullet may have lost weight and if it's mushroom heavily then it may have dumped more energy that a bullet which is for example more solid and hasn't deformed as much.

3. Unless you could measure the exit velocity of the bullet, I don't think it's possible
(Someone will turn up to prove me wrong!!)

Cheers

Bruce

4. What difference does it make? If it passed through it didn't utilize all the energy available. If you find the mushroomed bullet in the carcass, it did. In any event, its all after the fact and not predictable.~Muir

5. Originally Posted by Muir
What difference does it make? If it passed through it didn't utilize all the energy available. If you find the mushroomed bullet in the carcass, it did. In any event, its all after the fact and not predictable.~Muir
I agree with this view: and the answer to the OP's question is, I think, 'no'.

You'd need to know the velocity of the bullet (not the round, of course) just before it hit the deer - which actually is knowable.
The velocity and mass of what's left of the bullet as it leaves the deer really isn't knowable I think becuase, as Muir says, there are too many variables.

6. Yes, you could. In theory. But what would the reason for wanting to know this, though? It'd be an awful lot of theoretic calculations for no reward

7. How about just getting a deer carcass that has been shot somewhere other than in the chest and rigging it up with a chronograph behind it and then shooting it and see what you get.

Any reason that wouldn't work?

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8. Originally Posted by tomblincoe
How about just getting a deer carcass that has been shot somewhere other than in the chest and rigging it up with a chronograph behind it and then shooting it and see what you get.

Any reason that wouldn't work?
As long as the bullet came out just over where the chronograph was, and you didn't mind a chronograph full of claret and bits, I guess it would work fine for that one bullet on that one occasion.

9. Originally Posted by Dalua
As long as the bullet came out just over where the chronograph was, and you didn't mind a chronograph full of claret and bits, I guess it would work fine for that one bullet on that one occasion.
All very true! Theoretically there is no reason it shouldn't give you data for that particular (single) shot

Practically however it would be messy, could be expensive and there are too many variables to make it meaningful or useful...

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10. Wouldn't you need to do it at least three times then use the average ?

Paul

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