A new debate

[lerch]

How ya'll doing??

Well about a year ago when i was brand new on the forum I posted a question about bullet penetration vs. a bullet depositing all of its energy inside a animal. The question got some useful answers and also started a argument too, like all good questions do. I have since read most of those posts and I have altered my original stance. I no longer believe a bullet depositing all of its energy inside of a animal is enough to kill, you can get swarzenager, no way i spelled that right, to whack a elk with a sledge hammer in the shoulder and I doubt it would kill it on the spot.

My question is this. What do you guys think is more important, overall bullet diameter or retained energy on impact???

Which would be better, a 224 diameter bullet impacting a animal with 3000 ftlbs or a 45 cal bullet hitting a animal at 1500fps???

I guess my overall question is where is the drawing point between speed and carried energy and enough bullet diameter to impart a massive wound channel??

Say you have a very small diameter bullet, 22cal for example, even with a heavy weight bullet if it doesnt expand you still have a relatively small wound channel. IF this bullet is heavy for caliber and traveling at a great rate of speed you will certainly have the substantial ft lbs of energy ammo makers love to advertise. BUt if the bullet doesnt expand much then what you are left with is still a relatively small wound channel.

Likewise if you have a large diameter bullet traveling at a relativly low rate of speed you would have the initial massive wound channel but without the retained energy where is the inertia to propel the bullet forward into the animal.

So where is the give and take point?? Which is better, to have a massive brick that imparts tremedous stopping power to the animal or a smaller bullet that retains much more energy and drives completly through the animal??

Sorry if i do not pose the questin very clearly, my mind works at a different speed than my hands, i will not say who is quicker
/ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif
thanks
steve

 

[Michael Eichele]

Alot of it has to do with the size of the critter.

Pure shock will go along way with a deer and not as far with and elk. One needs energy to penetrate bigger game but also needs a big hole to air and bleed out. If a 30 cal FMJ bullet carrying 4500 pounds of energy blows through and elk, there is hardley any energy transfer and a small hole. THIS IS BAD! A 284 cal bullet carrying 2000 pounds of energy that opens and makes a good hole will do its job quickly. If you plan on shocking an elk you better be packin big bullets that open up and drive em fast. Most important is to have sufficient energy to open the bullet and penetrate the vitals fully. For deer, pick an accurate load that either shocks the crap out of em ie: high velocity and rapidly expanding bullets (bang; flop) or a load that opens with less energy creating a proper wound path and airs them out. Both will get the job done.

Arrows with or without broadheads have minimal energy but arrows with broadheads create big wound channels and kill VERY quickly. Look to the arrow for your answer.

 

[Buffalobob]

Energy vs monentum

For shooting large game animals (things bigger than a squirrel).

I think the last time this came up in any significant way Kirby wrote a rather detailed response which was pretty much in line with what I think. My thoughts are something like the Taylor Knock down Index (TKI) plus bonded bullet (Taylor being an African game hunter used a lot of solids so it is pretty similar). Taylor throws energy in the trash can where it belongs. Energy, like a stray dog with the mange will not stay runoff but keeps on coming back around. The TKI uses the bullet mass, the velocity and the bullet diameter. Mass times velocity is Momentum. Energy is mass times velocity squared. Using momentum one would find that a 17 Rem firing a 25 grain bullet at 4000 fps would be equal to a 50 grain bullet at 2000fps or a 100grain bullet at 1000 fps. From a momentum standpoint the little light bullet prevents the 17 Rem from developing any significant momentum. However if one starts using energy then the 17 rem starts to look more like a deer killing caliber because it has a lot of velocity which gives it a good bit of energy even though we know it is not.

It is fairly obvious that the larger the bullet diameter the bigger the hole that will be made in an animal as long as you get similar penetration. We can get into some absurd situations of large diameter low sectional density bullets versus smaller diameter high sectional density bullet, say for example a 257 caliber bullet in 110 grains versus a 308 bullet in 110 grains.

Let us switch to bullet construction. Frangible bullets like varmint bullets are designed to expand violently on contact even to the point of disintegration. Once they have broken into smaller particles they have lost a lot of energy through "inelastic deformation". This ripping apart of the metal lattice structure causes a huge lose of velocity and the bullet momentum is greatly reduced which means it will not penetrate well. A full metal jacket, solid or bonded bullet does not "disintegrate" into small pieces and "mushrooming' is very controlled so not much mass nor velocity is lost and momentum is retained to keep on penetrating. At the margins of a bullets range, if one is shooting a bullet such as an Amax and impact a large shoulder bone the bullet may lose so much energy through inelastic deformation (bullet just flattens out and goes splat on the bone) that it will not break the bone. In other words the bullet needs to be harder than the bone once the momentum has dropped into a marginal range. At closer ranges where there is excess momentum one can afford to lose some energy by inelastic deformation. As mentioned above "sectional density" is an index that tells us what the likelihood is of a bullet retaining a significant amount of mass upon impact. ( As a foot note to the reader I have been very careful to be very technically correct when using the term energy and momentum being as these terms are interrelated but different in their properties. Momentum must be conserved but you may lose energy. A true analysis will convert momentum into an impulse analysis)


What is so great about a 7mm 200grain bonded wildcat? Long range delivery of high mass and high velocity with bone breaking toughness. Ever body gets all wound up over th BC but even with just a decent BC such as you would get with a Sierra match king the extra mass is what makes the bullet so formidable at long range. Bonded toughness (assuming it is comparable to a nosler accubond) keep it from too much losing energy and extend its useful range.

The one point I would make on an arrow is that what it does is penetrate. No hide blowups, no deformation energy loss from inelastic collisions, no soft lead and thin copper jackets.