I too have my doubts about any one number telling you if you have enough bullet for the job. Some think that 1000 ft*lb is required, others feel comfortable with 800. But I have never heard anyone say that a 357 magnum pistol isn't up to the job and they only produce a little over 400 ft lbs at 50 yards.
I wonder if anyone ever did a test to see how much energy you can expend into a deer's chest? Sort of like an Izod impact test to see how tough steel is. I think a lot of variables would come out as more important than currently thought, such as impact velocity as Shakey mentioned. But once you punch through the deer, any remaining energy is wasted on the surroundings. So if a 308 will pass through a deers chest at X yards, why would you need a 300WinMag at double the energy? Do you like digging big holes? Now if you are shooting the 300WM at a range where the energy level is back down to the 308 level, that is great. But so many of the hunters I know carry 300WM's and would never consider shooting over 100 yards. I don't think the deer is going to be any more dead with a 300WM than with a 243 at that range, but I'll bet that the shooter isn't as likely to be as good with it.
I think that we may have gotten ourselves into a vicious circle. Someone speculates that X ft*lb would work. The next guy doesn't want to get caught short handed and so he pads his number 10-20% when asked what should be used. After a few of these we may where we are today. Nobody knows, but everybody comes up with a number.
"When working with the public, there are two things you need to remember. - 1. The public is a bunch of ignorant morons. - 2. YOU and I are one of them!"
The above bullet is a 159gr EXP Groove Bullet shot from a 300 win mag with a velocity of 3377 FPS, measured 10 feet from the muzzle.
The above bullet is a 159gr EXP Groove Bullet shot from a 30-06 with a velocity of 1808 FPS, measured 10 feet from the muzzle.
Both bullets were shot into metal cans, filled to the top with water, caps secured, stacked 1" apart in a line - at 100 yards.
As seen in the top picture the petals of the bullet came off, as designed. The Base of the bullet was found inside the 7th can.
As seen in the bottom picture the bullet expanded very little due to the low velocity. The bullet did not loose its petals. The bullet, as shown went through 6 cans and dented the front of the 7th can.
The penetration was almost the identical in both cases yet because the bullet shot from the 30-06, started out at such a low velocity it didn't deform much.
The energy levels of the 2 were drastically different. The fact that the top bullet expanded, slowed penetration.
<BLOCKQUOTE><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><HR>... Also,energy goes both ways. While pulling the trigger,you receive the same amount of energy as the bullet has. If itīs the energy that does the job,nobody should be able to kill anything weighing more than the shooter -without passing out,huh?<HR></BLOCKQUOTE>
No, Petander, you do NOT receive the same amount of energy that the bullet has; you receive the same, actually a little more, MOMENTUM that the bullet has when it leaves the muzzle. You receive more momentum because the powder being expelled from the muzzle adds to the momentum. Momentum is mass times velocity. Energy is one-half times the mass times the velocity squared. A big difference.
Energy is of little concern to me. The above comments regarding .357 Mag and arrow performance illustrate the fallacy of using it as a benchmark. Placement and bullet performance are all that matter. Yeah, I know it takes energy to get there, but...
Perhaps the energy that is pertinent is stored in the amount of powder you burn. What you do with it is another story.
Energy is important. With zero energy no damage would be done to the animal and you would not kill it.
But like everything else, it's only one factor of many that is important. You need to use a little common sense and not ignore other important factors like many of the examples given above illustrate.
Let's take Don's test for example. Same bullet, roughly the same penetration. Is that all that's important?
Which bullet did more damage to the cans of water? Which blew bigger holes through their sides? Which blew the lids higher in the air? Which would do more damage to the lungs of an animal?
Personally, I wouldn't shoot an animal through the lungs if the bullet was going to end up looking like the low velocity bullet pictured. Same bullet, it just didn't have enough energy to do any damage to itself (expand) and likely wouldn't do much damage to the animal. Give me an A-Max, BT, SST, SMK, AB, etc, bullets that don't need much energy to expand and inflict damage.
There's an example right there of how energy is important, but not the only important factor. If you're shooting an animal through the lungs at extremely long range, you don't need enough penetration to go through 3 or 4 animals if they happened to be standing side-by-side. You need to do damage to the first animal. One type of bullet may get that done with the same amount of energy that another wouldn't. You only have a little energy left, don't waste it.
Spitzer FMJ bullets are illegal to hunt with in most states for that very reason--they can pencil through the lungs punching only a tiny hole and increase the likelyhood of wounded game getting away. I used X bullets a lot in the past and light ones at high velocity were devistating at normal ranges. However, since I've become more proficient at longer ranges, I don't really trust the solid copper bullets to open up and do much damage when the range gets long.
I should say that's only from my own testing with X bullets. I haven't tried Don's or other solid copper bullets. But my personal preference will be to stay with plastic tipped bullets for a while, I think.
Looking at energy as a means of penetration, using the bullets shown above it can be determined that energy means little. The "needed" energy to open up a bullet is another matter. If one bullet "needs" 500 fpe to open up and another "needs" 800 fpe to open up then those are the numbers we should consider, not that any bullet requires a certain fpe to be an effective killer of a certain animal.
The lower picture shows the bullet hitting the cans at about 1600 FPS. Our purpose of that test was to find the threshold of where the bullet opens up. Obviously it is higher then 1600 FPS. A smaller caliber bullet with a thinner cross section wouldn't require as much energy to open up. This is why one should consider bullet construction, materials and shape more so then just energy created.
There is no doubt that both of the examples listed (pictures) show that either of those would go clean through an elk, double lung, broadside. It is also true that the top picture results would cause more trauma then the lower picture shows.
My purpose of the 2 pictures was to disprove that energy does not equal penetration. I believe the 2 pictures and data obtained prove that.