Home Forums Hunting & Shooting Long Range Hunting Foot Lbs. Energy ???

When shooting long range, how much energy do you want to have when the bullet hits the intended animal? Is there a rule of thumb or does it depend mostly on bullet used?

I've got a book at home that details how many foot lbs of energy that it takes to humanely kill various game animals, but I take those figures with a grain of salt, they're a guideline at best.
If memory serves me correctly it's 600 ft. lbs on target for deer and other thin-skinned non-dangerous animals and 1000 for elk sized animals. If I remember, I'll check tonight.

There are so many variables....my opinion is, just use a proven caliber and bullet for the particular game you're hunting and you will be fine.

The main thing you want to look at is the bullet's velocity, and make sure it's within the design parameters for terminal performance which for most is above 1800 fps.

Energy? We don't need no stink'in Energy. We need enough velocity to insure the bullet will open.

Alan

an arrow may have under 100 ft lbs and still be lethal,its not FT LBS but proper placement or impact point of a bullet designed to expand and penetrate deeply in a controlled manor , and push thru the vitals from most reasonable ranges and angles and knowing the animals anatomy that's critical.
I can tell you from experience that a 44 mag loaded like the chart below is 100% effective on deer out at 150 yards where you have less than 600ft lbs

Your Input Variables
Ballistic Coefficient 0.2 Velocity (ft/s) 1200 Weight (grains) 240
Maximum Range (yds) 300 Interval (yds) 50 Drag Function G1
Sight Height (inches) 1.5 Shooting Angle (degrees) 0 Zero Range (yds) 100
Wind Speed (mph) 0 Wind Angle (degrees) 90 Altitude (ft) 0
Pressure (hg) 29.53 Temperature (F) 59 Humidity (%) 0.78
Ballistics Results
Range (yards) Velocity (fps) Energy (ft.-lb.) Trajectory (in) Come UP in MOA Come UP in Mils Wind Drift (in) Wind Drift in MOA Wind Drift in Mils
Muzzle 1200 767 -1.5 0 0 0 0 0
50 1108 654 2.8 -5.3 -1.6 0 0 0
100 1038 574 0 0 0 0 0 0
150 984 516 -10.8 6.9 2 0 0 0
200 940 471 -30.7 14.6 4.3 0 0 0
250 902 433 -60.3 23 6.7 0 0 0
300 868 401 -100.7 32 9.3 0 0

but you can make reasonable choices, in caliber and if you choose a quality bullet design with at least a .270 minimum sectional density
a .450 or better ballistic coefficient, and push it to at least about 2700fps youll generally have good results out to well past 500 yards
it should be obvious that given rifles of reasonably similar weight, that as bullet weight and velocity increase so does recoil, so you might want to consider that as well.
heavier bullets in a caliber tend to retain momentum and energy more efficiently.
personally Id suggest nothing smaller than a 270 caliber 150 grain bullet at at least 2700fps as a starting point on an elk rifle to be used out at longer ranges
Ive found the .338 225-250 grain bullets are ideal but you can certainly use the 7mm-160-175 grain, or 30 caliber 180-200 grain bullets pushed to 2700 fps or faster to get good results
heres a ballistic calculator

http://www.hornady.com/ballistics-resource/ballistics-calculator

http://www.beartoothbullets.com/rescources/calculators/php/density.htm?bw=250&bd=.338

Foot pounds of energy is. Very poor indicator of lethality. The ballistic pendulum shows what happens to FPE in a bullet strike which is an in elastic collision.

Kind of what I figured but I was mostly curious if there was a set number. So for the most part not. I for the most part hunt elk with only 2 rifles. The first is a 350 Rem mag shooting 225 Sierra's at 2600, I won't shoot it must past about 350, maybe 400 on a stretch. It drops off pretty quickly past 350. My other is a 300 Weatherby shooting a 200 grain bullet at 3000 fps. It will shoot farther than I can. I have never practiced past 500 yds and won't shoot game past that distance. Thank you for all the input.

You are well within the limits of those rifles. I don't know much about physics and energy, but I do know about killing deer. For me and any advise I would give is deer are not hard to kill, and not all go bang flop short of a CNS shot. It is much easier to kill a deer up close with little energy due to precise shot placement. As things get longer it is harder to precisely place a bullet and this is where the low energy small projectiles can get you in trouble. A large bullet cant always make up for a less than perfect shot, but on a marginal shot I sure as hell would rather hit a deer with a 300 grain SMK out of my Norma than a 107 out of my 6br.

I no longer believe in FPE as a requirement. I have killed too many animals where the experts and their favored formula's were proven irrelevant.

I have shot clear through 200 pound animals at ranges requiring 4 feet holdover with tiny pills like the 53gn TSX launched from a .223. BC, SD, talking points from a past era.

For me, bullet construction is a far greater influence than ballistic theory.

I don't believe the energy numbers are irrelevent, but are often mis interpreted. We all know that it is bullet placement, penetration, and wound size (whether from bullet diameter or expansion) that kills stuff. If we are comparing bullets of similar construction, velocity and diameter etc., the energy numbers can be a fairly accurate predictor of the damage.

I've long read that around 1000 ft lbs for deer and 1500 for elk was a good rule of thumb with a little margin for error built in. We all know it can be done with less energy, but the chances of wounding go up as energy numbers drop below these numbers. If we are all using conventional cup and core bullets from standard rifles like 270, 308, 30-06 etc that is probably fairly accurate.

But energy numbers don't factor in everything. Heavy 400 gr bullets from a 45-70 will still penetrate deep and destroy lots of body parts with far less energy. Same for an arrow or many premium bullets available today.

A BB size hole in the right place will eventually kill any land animal in the world. The problem is making that hole and how much time you want the game to be up and about after the shot. The same thing applies to game as to humans, and there's a difference between killing power and stopping power and in some cases your own life depends on stopping power.

Think of energy as insurance. If your shot is off the mark, or your bullet doesn't work as advertized then energy becomes paramount. Even if the affect of the energy proves temporary it can give you time for a second shot.

Obviously, it can be overdone. You really don't need a .338 Lapua Mag for varmint hunting unless the critters are in the next county.

I think energy can come in pretty handy when hitting large bones on large animals. I would not want to hit a Blue Wildebeest at long distance with too little energy left to penetrate large bones. Small projectiles can have all the speed in the world and simply not have the energy to go through large bone, or be deflected from bone and missing your aiming point. I think energy can come in pretty handy This is what I have noticed while guiding and why plenty of guides carry 375h&h and not 220swifts. I know my experience has to do with normal hunting distances but the same thing counts when the bullet hits the animal.

Pieter

At long range?

In the real world plans don't always work out and sometimes you find yourself close to dangerous game.

I believe the question (and the forum) was/is long range.

Maybe we should ask the bus loads of members here who shoot anything they please with the 7/08 and 120gn TSX.

Ay what range should they stop shooting because the energy has fallen below a threshold?

If there was any fact in this with today's bullet technology, we'd all have to carry range finders so we know when to "not" shoot.

It's the transference of the remaining energy at point of impact that's important. Location of impact in anatomical terms is important of course. Many other factors are added in also.

loss of blood pressure kills animals , damaging /disabling their nervous system will immobilize them . The necessary energy argument was lost on me bowhunting , however when long range hunting I have paid a bit more attention to required velocity parameters for bullet "performance" to achieve the loss of blood pressure thing. I will be the first to admit that energy is never a bad thing when long range hunting. The big 30's 7's and 338's cover the velocity and energy dilemma quite well. I also like bullets that transfer that energy into the target for LRH , ie; VLD's. My point is that I dont think all your eggs need to go into one basket: metal vs. meat isnt really a fair fight/ metal wins every-time.

One need not believe in torque multiplication--his car still gets him to work. Same with FPE, BC, SD...

Everyone has seen computer-generated likenesses done with X's and O's creating a somewhat vague image. Same with FPE, BC, SD--reading the data helps some of us envision what to expect from a particular cartridge. Like comparing the reach and weight and wins/losses of two fighters gives us a feel for what to expect, even though it doesn't tell the whole story or pick the winner.

I agree with Alan. It's the bullet expansion that destroys tissue and that's what kills.