bullet energy limit

[35 Whelen]

This some thing I have found a bit amusing over the years and have not been able to get an answer to. So I thought I but on hear and see what every one on here thinks.

When I started reading hunting magazines in my early teens I was reading that a cartridge reached it's limit at 900 ft. lb. of energy. As time has gone by (30 + years) it has gone up. From 900 to 1000 to 1400 and now 1500. What has made the increase? I don't think the game animals have changed, and we do have better bullets.

Just wondering what every one thinks on this and share your thoughts. Do we just want more power?
This may all so be a good way to help some one pick a new rifle or a new hunter pick their first hunting cartridge.

 

[birdiemc]

Kinetic energy is physics
ke=.5 x mass x velocity squared.
For shooting we have to add in the acceleration due to gravity to convert from weight to mass and convert from grains to pounds so the formula becomes
Ke= grains x velocity squared/ 2 x 7000 x 34.17
The 34.17 is relative to lat/long and elevation but that number is the accepted one to use.
I dont understand how a cartridge could reach max energy of 900ft/lbs so long as velocity and bullet weight are high enough.
The actual energy of a loaded round is less straight forward because the potential energy of the propellant charge gets converted to sound, heat and kinetic energy of the bullet, so not all the energy goes into propelling the bullet, one example in a ballistics book I was reading just this morning calculated the actual energy propelling the bullet to be only 27%.

 

[J E Custom]

I hope I am not confused on this question so I will give my understanding of this question.

Most big game animals have a recommended ft/lb on impact that is considered best. Less energy will still kill but the desired results may not be what you need or want.

These energies were call Taylor knock out values and they were just a guide to aid the hunter in game recovery.

Deer size animals required 900 to 1200 ft/lbs of energy.
Elk sized animals was 1500 to 2000 ft/lbs of energy.
With Dangerous game like bears and moose 2000 to 2500.ft/lbs was considered necessary.
For the big dangerous game of Africa 3000 + and for the really big stuff some felt like it should be over 4000 ft/lbs +

With today's bullets and firearms these numbers may be a little much but is is still a good reference point to use if you are not experienced or you are not sure. (In other words, It can't hurt) shot placement is still very important with any shot and energy level.

J E CUSTOM

 

[birdiemc]

Dang looks like I had the right answer to the completely wrong question... lol

 

[Blackdirt Cowboy]

Dang looks like I had the right answer to the completely wrong question... lol

I was still impressed.

 

[J E Custom]

Dang looks like I had the right answer to the completely wrong question... lol

Hey, I probably didn't understand the question

J E CUSTOM

 

[35 Whelen]

I hope I am not confused on this question so I will give my understanding of this question.

Most big game animals have a recommended ft/lb on impact that is considered best. Less energy will still kill but the desired results may not be what you need or want.

These energies were call Taylor knock out values and they were just a guide to aid the hunter in game recovery.

Dear size animals required 900 to 1200 ft/lbs of energy.
Elk sized animals was 1500 to 2000 ft/lbs of energy.
With Dangerous game like bears and moose 2000 to 2500.ft/lbs was considered necessary.
For the big dangerous game of Africa 3000 + and for the really big stuff some felt like it should be over 4000 ft/lbs +

With today's bullets and firearms these numbers may be a little much but is is still a good reference point to use if you are not experienced or you are not sure. (In other words, It can't hurt) shot placement is still very important with any shot and energy level.

J E CUSTOM

I all ways like your post, understandable and to the point. I think what has made it so confusing for many is most gun writers spit out a number but do not state what game their are referring to. This makes some deer hunters thing they need a grizzly bear cartridge or an moose hunter think he is fine with a varmint/deer cartridge. Not that it can't be done, just not the best choses.

 

[35 Whelen]

Dang looks like I had the right answer to the completely wrong question... lol

It is still a very good answer, I liked it.

 

[35 Whelen]

So far all the responses are good, I hope they keep coming.

 

[sp6x6]

Yes and on this forum the discussions go to weather the bullet at that said energy level,can still open up and perform.Due to the velocity,etc and bullet type.

 

[birdiemc]

Yes and on this forum the discussions go to weather the bullet at that said energy level,can still open up and perform.Due to the velocity,etc and bullet type.

And that's where things get interesting....load em backward lol.

 

[lancetkenyon]

My PERSONAL criteria: whichever comes first.
1800fps minimum regardless of what animal
For pronghorn/deer sized game and down, 1000ft/lbs
For bear/elk sized game, 1500ft/lbs
I have never hunted anything bigger than elk like moose yet, but I think I might even go up to 2000ft/lbs in that case.

 

[Sevy]

I think the reason you haven't ever gotten a straight answer is because it isn't written somewhere in black and white like a rule. It's more of a personal preference. I think a person needs to take into account bullet construction and their ability to make a good shot rather than a number value. A .22 lr would kill an elk if you hit it in the right place and it penetrates. When discussing ft lbs of energy I believe we are discussing the "shock" of the hit rather than the placement. If the bullet will penetrate the hide than it will kill the animal, assuming it is hit in the right spot. With that said I think JE Custom got it right with the numbers. That's why the lack of straight answer in my opinion.

 

[memtb]

With 1500 ft/lb for elk minimum, it looks like I'm good to about 770 yards.... about 170 farther than my self-imposed big game, range limit! memtb